323 results on '"Masakiyo Matsumura"'
Search Results
2. Ultrahigh-Performance Polycrystalline Silicon Thin-Film Transistors on Excimer-Laser-Processed Pseudo-Single-Crystal Films
- Author
-
Yukio Taniguchi, Shigeyuki Shimoto, Takahiko Endo, Takashi Okada, Tomoya Katou, Genshiro Kawachi, Kazufumi Azuma, Shinzo Tsuboi, Takashi Ohno, Masahiro Mitani, and Masakiyo Matsumura
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Excimer laser ,business.industry ,Phonon ,medicine.medical_treatment ,Transistor ,General Engineering ,General Physics and Astronomy ,Electron ,engineering.material ,Threshold voltage ,law.invention ,Polycrystalline silicon ,Thin-film transistor ,law ,medicine ,engineering ,Optoelectronics ,Grain boundary ,business - Abstract
Thin-film transistors (TFTs) were fabricated on polycrystalline silicon (poly-Si) films formed by position-controlled large-grain growth technology using an excimer laser. The field-effect mobility, on-off transition slope, and threshold voltage were 914 cm2 V-1 s-1, 93 mV/decade, and 0.58 V for the n-channel device, and 254 cm2 V-1 s-1, 122 mV/decade, and -0.43 V for the p-channel device, respectively. These values indicate that TFTs had an ultrahigh performance comparable to that of {100}-oriented crystal-silicon metal–oxide–semiconductor (MOS) transistors. Furthermore, their effective mobilities had the same effective field and temperature dependences as those of MOS transistors, indicating that electrons and holes were predominantly scattered not by random grain boundaries or defects in the Si film, but by phonons at the SiO2–Si interface, similarly to those of crystal-silicon MOS transistors. These attractive results were obtained as a result of the fact that the TFT channel region was made up of nearly {100}-oriented single grains.
- Published
- 2008
3. Ultralong Silicon Grains Grown by Excimer Laser Crystallization
- Author
-
Takahiko Endo, Takashi Ohno, Masakiyo Matsumura, Tomoya Katou, Kazufumi Azuma, Shigeyuki Shimoto, and Yukio Taniguchi
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Silicon ,business.industry ,General Engineering ,food and beverages ,General Physics and Astronomy ,chemistry.chemical_element ,Grain growth ,Light intensity ,chemistry ,Thin-film transistor ,Optoelectronics ,Waveform ,Elongation ,business ,Layer (electronics) ,Intensity (heat transfer) - Abstract
The factors affecting the elongation of Si grains were investigated for the excimer-laser-induced lateral grain growth method. The length of Si grains was found to depend on the laser light intensity profile, the waveform of the laser light pulse, particularly at its tail region, and the sample structure. Grains as long as 25 µm were successfully grown at room temperature using a combination of a V-shaped light intensity profile, a light pulse waveform with a long tail, and a stacked sample structure with a cap layer. Grains of 11 µm in length were also grown in a capless sample.
- Published
- 2008
4. Pseudo-Single-Nucleus Lateral Crystallization of Si Thin Films
- Author
-
Kazufumi Azuma, Yukio Taniguchi, Takashi Ohno, Tomoya Katou, Masakiyo Matsumura, Takahiko Endo, and Shigeyuki Shimoto
- Subjects
Diffraction ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,business.industry ,General Engineering ,General Physics and Astronomy ,Electron ,law.invention ,Light intensity ,Optics ,medicine.anatomical_structure ,Thin-film transistor ,law ,medicine ,Irradiation ,Thin film ,Crystallization ,business ,Nucleus - Abstract
We have developed a method of preselecting a lucky nucleus among many simultaneously born nuclei for the growth of position-controlled large single Si grains by excimer-laser-induced lateral crystallization. Using this method, arrays of large Si grain of almost 5 ×5 µm2 size were successfully grown with a single shot. The result of electron backscattering diffraction pattern (EBSP) analysis indicated that most of the large Si grains had no random boundaries inside, which means that each grain grew from only a preselected lucky nucleus. It was confirmed that the margins to the vertical mispositioning of the sample surface from the focal point and also to the fluctuation of average irradiation light intensity were sufficiently large. Therefore, our method seems to be very attractive for industrial applications.
- Published
- 2008
5. Novel Optical Method for Widening Process Window of Phase-Modulated Excimer Laser Crystallization
- Author
-
Kazufumi Azuma, Takahiko Endo, Hiroshi Ishiwara, Masakiyo Matsumura, and Yukio Taniguchi
- Subjects
Depth of focus ,Materials science ,Birefringence ,Physics and Astronomy (miscellaneous) ,Excimer laser ,business.industry ,medicine.medical_treatment ,General Engineering ,Phase (waves) ,Physics::Optics ,General Physics and Astronomy ,Ray ,Light intensity ,Optics ,Optical path ,medicine ,Process window ,business - Abstract
A wide process window has been achieved for "the phase-modulated excimer-laser annealing" method of Si thin films. Ordinary and extraordinary light rays resulting from the birefringence effects of a crystal quartz plate, which is newly introduced within the optical path of the annealing system, generate a pair of projected images of a phase modulator. By adjusting their separation to be half the modulator pattern pitch, undesirable deformations, which appear in pair images owing to defocus, cancel each other out, resulting in a stable superposed image (light intensity profile) on the sample surface. It is shown by optical simulation and experiment that this "double-image method" widens the depth of focus from less than 2 µm to as wide as about ±6 µm.
- Published
- 2008
6. Influences of Grain Boundaries on Temperature Dependence of Device Characteristics and on Hot Carrier Effects in Low-Temperature Polycrystalline Silicon Thin Film Transistors Containing Large Grains
- Author
-
Masakiyo Matsumura, Toshiaki Tsuchiya, Takafumi Miura, Tsubasa Yamai, and Genshiro Kawachi
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Low-temperature polycrystalline silicon ,General Engineering ,Nanocrystalline silicon ,General Physics and Astronomy ,engineering.material ,Subthreshold slope ,Threshold voltage ,Polycrystalline silicon ,Band bending ,Thin-film transistor ,engineering ,Grain boundary - Abstract
The dependences of field-effect mobility, threshold voltage, and subthreshold slope on temperature for low-temperature polycrystalline silicon (LTPS) thin film transistors (TFTs) with large grains were investigated. It was shown that the temperature dependences of field-effect mobility and threshold voltage are affected by the temperature dependence of negatively charged grain-boundary-related interface traps near the surface of polycrystalline silicon, which is explained by considering that the degree of band bending at the surface when gate voltage is equal to threshold voltage decreases with increasing temperature. It was also shown that the behavior of a subthreshold slope can be explained using a term of the grain-boundary-related interface traps near the surface. Moreover, the effects of grain boundaries on hot-carrier generation and hot-carrier-induced degradation were investigated separately, and both processes were experimentally found to be affected by the grain boundaries.
- Published
- 2007
7. Proposed Phase-Modulator Check System for Phase-Modulated Excimer-Laser Annealing
- Author
-
Yukio Taniguchi, Kazufumi Azuma, and Masakiyo Matsumura
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Excimer laser ,business.industry ,Annealing (metallurgy) ,medicine.medical_treatment ,General Engineering ,General Physics and Astronomy ,law.invention ,Light intensity ,Wavelength ,Optics ,Optical modulator ,law ,Thin-film transistor ,medicine ,Optoelectronics ,Crystallization ,business ,Phase modulation - Abstract
The fluctuation of the light intensity distribution on a sample surface has an adverse effect in lateral Si crystallization methods, such as phase-modulated excimer-laser annealing (PMELA). Consequently, the origins of various fluctuations must be examined precisely and suppressed satisfactorily and independently. In particular, the phase modulator, which mainly determines the microscopic light intensity distribution, must be checked carefully. We have developed a stand-alone visible-light check system for phase modulators, by taking different wavelength effects into account, and have confirmed the usefulness of the system.
- Published
- 2007
8. Characterization of High-Performance Polycrystalline Silicon Complementary Metal–Oxide–Semiconductor Circuits
- Author
-
Hiroyuki Ogawa, Terunori Warabisako, Masayuki Jyumonji, Genshiro Kawachi, Kazufumi Azuma, Noritaka Akita, Yoshiaki Nakazaki, Masato Hiramatu, and Masakiyo Matsumura
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Transistor ,General Engineering ,General Physics and Astronomy ,Short-channel effect ,Ring oscillator ,Propagation delay ,engineering.material ,law.invention ,Threshold voltage ,Polycrystalline silicon ,CMOS ,law ,Thin-film transistor ,engineering ,Optoelectronics ,business - Abstract
Polycrystalline silicon (poly-Si) complementary metal–oxide–semiconductor (CMOS) circuits have been fabricated by using an advanced excimer-laser annealing method and a plasma-oxidation method. The 1-µm-long thin-film transistors (TFTs) were fabricated on arrays of laterally grown long and narrow grains, so that the majority of carriers were free from scattering at grain boundaries during propagation through the channel. The propagation delay time measured by a 21-stage ring oscillator was 175 ps and a power-delay product of 9×10-13 J/gate was obtained at a supply voltage of 3.3 V. The obtained propagation delay time was almost the same as those of bulk Si devices having the same gate length. Furthermore, we expect that 1-µm-long CMOS TFT circuits on glass will have a performance superior to that of 1-µm-long bulk Si devices when the short channel effect and threshold voltage fluctuation are controlled well.
- Published
- 2007
9. Importance of Pure Si Films in Pulsed-Laser-Induced Lateral Growth
- Author
-
Noritaka Akita, Masayuki Jyumonji, Hiroyuki Ogawa, Yoshinobu Kimura, Tomoya Katou, Masakiyo Matsumura, and Masato Hiramatsu
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Silicon ,Inorganic chemistry ,General Engineering ,General Physics and Astronomy ,chemistry.chemical_element ,engineering.material ,Oxygen ,Polycrystalline silicon ,chemistry ,Chemical engineering ,Impurity ,Thin-film transistor ,engineering ,Fluorine ,Layer (electronics) ,Carbon - Abstract
We have investigated the effects of impurities in starting silicon films on excimer-laser-induced lateral growth characteristics. The films should have a low concentration of impurities to achieve long lateral growth, since impurities, such as carbon, nitrogen, oxygen, and fluorine, in the films were found to affect the lateral growth characteristics severely. A stacked structure with a capping layer is also considered essential for maintaining pure molten Si during lateral growth.
- Published
- 2006
10. Characterization of Novel Polycrystalline Silicon Thin-Film Transistors with Long and Narrow Grains
- Author
-
Masato Hiramatu, Terunori Warabisako, Hiroyuki Ogawa, Masakiyo Matsumura, Genshiro Kawachi, Kazufumi Azuma, Masayuki Jyumonji, and Yoshiaki Nakazaki
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,Transistor ,General Engineering ,Nanocrystalline silicon ,General Physics and Astronomy ,Field effect ,engineering.material ,law.invention ,Grain growth ,Polycrystalline silicon ,Thin-film transistor ,law ,engineering ,Optoelectronics ,Grain boundary ,business ,Material properties - Abstract
Excellent characteristics of polycrystalline silicon (poly-Si) thin-film transistors (TFTs) with long and narrow grains aligned one-dimension have been experimentally clarified for the first time. The field effect mobility and on-off transition slope of n-channel and p-channel devices were as high as 685 cm2 V-1 s-1 and 190 mV/decade and 145 cm2 V-1 s-1 and 104 mV/decade, respectively. Fluctuations of characteristics were considerably reduced by widening the channel, and uniform characteristics were observed when there were approximately twenty long grains within the channel. These results were obtained when the TFT channel was formed within a region free from grain boundaries formed by head-on collision of laterally growing grains and seeds used to initiate lateral grain growth. Material properties are discussed from the viewpoint of device characteristics.
- Published
- 2006
11. Crystallization Technology of Si Thin Films for Future TFTs
- Author
-
Masato Hiramatsu, Kazufumi Azuma, and Masakiyo Matsumura
- Subjects
Materials science ,business.industry ,law ,Optoelectronics ,Thin film ,Crystallization ,business ,law.invention - Published
- 2006
12. Optimum Light Intensity Distribution for Growing Large Si Grains by Phase-Modulated Excimer-Laser Annealing
- Author
-
Masakiyo Matsumura, Hiroyuki Ogawa, Yoshinobu Kimura, Masayuki Jyumonji, Yukio Taniguchi, and Masato Hiramatsu
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Excimer laser ,business.industry ,medicine.medical_treatment ,General Engineering ,Physics::Optics ,General Physics and Astronomy ,Atomic packing factor ,law.invention ,Light intensity ,Optics ,law ,Phase (matter) ,medicine ,Physics::Atomic Physics ,Thin film ,Crystallization ,business ,Intensity (heat transfer) ,Beam (structure) - Abstract
Characteristics have been investigated for both KrF excimer-laser light and KrF excimer-laser crystallization of Si thin films. The results were applied to design an optical system for growing densely packed and large grains. A high-resolution beam profiler confirmed that the laser light intensity distribution on the sample surface had a nearly ideal triangular form with a maximum-to-minimum intensity ratio of approximately 2, as designed. This distribution could grow 5-µm-long grains with a packing efficiency close to 100% by a single laser light pulse.
- Published
- 2004
13. Effects of Light Intensity Distribution on Phase Modulated Excimer Laser Crystallization Characteristics
- Author
-
Yukio Taniguchi, Masato Hiramatsu, Yoshinobu Kimura, Masakiyo Matsumura, and Masayuki Jyumonji
- Subjects
Morphology (linguistics) ,Materials science ,Excimer laser ,business.industry ,Scanning electron microscope ,medicine.medical_treatment ,Electron ,law.invention ,Light intensity ,Transmission electron microscopy ,law ,Phase (matter) ,medicine ,Optoelectronics ,Crystallization ,business - Abstract
Microtexture was analyzed for Si films crystallized by a phase-modulated excimer laser annealing method, using Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Electron Back-Scattering Pattern (EBSP). Threshold fluences were identified for crystallization, lateral growth and film braking, by comparing the surface morphology and the microscopic excimer laser light intensity profile. It was found that {001} and {110} orientations are preferable for lateral growth direction but the surface orientation is random. A possible origin of preferable orientations for laterally grown film was discussed.
- Published
- 2004
14. Proposed Sample Structure for Marked Enlargement of Excimer-Laser-Induced Lateral Grain Growth in Si Thin Films
- Author
-
Wen-Chang Yeh and Masakiyo Matsumura
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Excimer laser ,Silicon ,medicine.medical_treatment ,General Engineering ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Grain size ,Grain growth ,chemistry ,Thin-film transistor ,medicine ,Thin film ,Composite material ,Layer (electronics) ,Buffered oxide etch - Abstract
60-µm-long grains were grown laterally in a 50-nm-thick Si layer on thermally grown oxide by a single shot irradiation of an excimer-laser-light pulse. The origin of such a marked (about 10 times) enlargement of grains can be found in a newly introduced photosensitive capping layer on the Si layer, which has been heated uniformly to extremely high temperatures by absorbing a fraction of excimer-laser-light and gradually transfers the stored heat to the Si layer after the laser irradiation, resulting in the extension of the liquid-phase duration of the Si layer. Ultrathinning the Si layer can effectively reduce the lateral heat loss along the highly heat-conductive, liquid or crystallized Si layer, and, in turn, extend the liquid-phase duration further. SiON and SiOC films are good candidates for the photosensitive capping layer, although SiOC is preferable since it can be etched by a buffered HF solution and has an appropriate light absorption coefficient for a broad band of laser-light-wavelengths.
- Published
- 2002
15. Characterization of initial one monolayer growth of Ge on Si(1 0 0) and Si on Ge(1 0 0)
- Author
-
Yasutaka Uchida, Keiji Ikeda, Jiro Yanase, Masakiyo Matsumura, and Satoshi Sugahara
- Subjects
Materials science ,Silicon ,Scattering ,Superlattice ,General Physics and Astronomy ,chemistry.chemical_element ,Germanium ,Heterojunction ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Molecular physics ,Surfaces, Coatings and Films ,Crystallography ,chemistry ,Monolayer ,Atomic layer epitaxy ,Spectroscopy - Abstract
One-monolayer deposition characteristics have been investigated for Ge on the Si(1 0 0) surface and Si on the Ge(1 0 0) surface by using a co-axial impact collision ion scattering spectroscopy. A subtracted spectrum method has been proposed for the detailed analysis of the interface structure. Incident angle dependence of the signal intensity shows that both Ge/Si and Si/Ge hetero-interfaces are atomically abrupt without intermixing and surface segregation.
- Published
- 2001
16. Optimization of phase-modulated excimer-laser annealing method for growing highly-packed large-grains in Si thin-films
- Author
-
Chang-Ho Oh, Masakiyo Matsumura, and Mitsuru Nakata
- Subjects
Materials science ,Silicon ,business.industry ,Annealing (metallurgy) ,General Physics and Astronomy ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,engineering.material ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Grain growth ,Light intensity ,Optics ,Polycrystalline silicon ,chemistry ,Thin-film transistor ,engineering ,Optoelectronics ,Phase-shift mask ,Physics::Atomic Physics ,Thin film ,business - Abstract
Optimization has been done theoretically for the phase-modulated excimer-laser annealing method to grow highly packed large grains in the Si film, where the divergence of the laser light beam plays an important role. Generalized optimum annealing conditions were given graphically as a function of the maximum-to-minimum light intensity ratio. Theoretical results were verified also experimentally by growing grains as large as 7 μm with 10 μm-pitch using a single shot of excimer-laser light pulse. It is pointed out that there is a room for improving the packing density to almost 100% by simply shortening the pitch of the phase shifters.
- Published
- 2000
17. Key Technologies for Next Generation Thin Film Silicon Solar Cells. Preparation of Ultra-Large Grain Silicon Thin-Films by Excimer-Laser
- Author
-
Masakiyo Matsumura
- Subjects
Materials science ,Excimer laser ,Silicon ,business.industry ,medicine.medical_treatment ,chemistry.chemical_element ,Nanotechnology ,Grain size ,Light intensity ,Grain growth ,chemistry ,medicine ,Optoelectronics ,Thin film ,Porosity ,business ,Thermal energy - Abstract
Advanced excimer-laser-annealing (ELA) technologies of Si thin films on glass have been reviewed. ELA-induced lateral grain growth seems attractive from an application view point since grains more than several microns in length can be grown by single shot of an excimer-laser light pulse. There are two technological ways for enhancing lateral growth kinetics. The one is introduction of non-uniform light intensity on the sample surface. Different values of thermal energy density stored in the molten Si film results in its solidification time delay along the sample surface, which triggers the long lateral grain growth. The other is an application of a non-uniform sample structure, which causes a non-uniform heat removal rate, resulting in the solidification time delay. An underlayer plays also very important role in ELA. By using organic SOG as the underlayer, grains more than 20 microns in length could be grown, and by using porous silica the grain size became more than 0.1 mm. These lateral growth technologies seem applicable not only to thin-film transistors but also to solar cells.
- Published
- 2000
18. Preparation and properties of silica films with higher-alkyl groups
- Author
-
Koh Ichi Usami, Takeo Hattori, Mitsuo Kobayashi, Satoshi Sugahara, Masakiyo Matsumura, and Kazuhito Sumimura
- Subjects
chemistry.chemical_classification ,Silicon ,Chemistry ,Infrared ,technology, industry, and agriculture ,Analytical chemistry ,chemistry.chemical_element ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,symbols.namesake ,chemistry.chemical_compound ,Fourier transform ,Chemical engineering ,Materials Chemistry ,Ceramics and Composites ,symbols ,Molecule ,Fourier transform infrared spectroscopy ,Absorption (chemistry) ,Alkyl ,Methyl group - Abstract
Silica films with various types of alkyl groups were grown from the liquid phase, at room temperature, using alkyl tri-alkoxy silane compounds. From Fourier transform infrared (FTIR) absorption measurements, a majority of Si-alkyl bonds in the source molecules were found to remain in the grown film, while Si-alkoxy bonds were completely removed. Electrical and thermal properties have been measured comparatively for various films having dense alkyl groups. The films with the methyl group are promising for silicon production in ultra large-scale integrated circuits (Si-ULSIs) and the film having the vinyl group for non-heat-tolerant compound-semiconductor large-scale integrated circuits (LSIs).
- Published
- 1999
19. Improved hydrogen free chemical vapor deposition of silicon dioxide
- Author
-
Masakiyo Matsumura, Kohshi Taguchi, and Yasutaka Uchida
- Subjects
Tertiary amine ,Hydrogen ,Silicon dioxide ,Analytical chemistry ,chemistry.chemical_element ,Chemical vapor deposition ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,chemistry ,Electrical resistivity and conductivity ,Materials Chemistry ,Ceramics and Composites ,Organic chemistry ,Amine gas treating ,Thin film ,Chemical composition - Abstract
Chemical vapor deposition parameters have been investigated for low (∼200°C) temperature deposited and hydrogen-free SiO 2 films from a mixture of tetra-iso-cyanate-silane and various kinds of tertiary-alkyl-amine. Di-methyl mono-ethyl amine was found the most suitable partner gas for H free low temprature CVD source gas mixture. Addition of small amount of H 2 O (0.5% of tertiary-alkyl-amine) was effective for decreasing the deposition temperature up to 50°C without serious drawbacks on the film properties such as hydration and electric properties. The deposition rate increased to higher temperatures by using those best partner gases, di-methyl mono-ethyl amine, with tetra-iso-cyanate-silane. The resistivity defined at 1 MV cm −2 was >10 16 Ω cm, and breakdown field strength at 1 μA cm −2 was >6 MV cm −2 . The fixed-charge density and interface sate density near midgap were ∼4 × 10 12 cm −2 and ∼10 12 eV −1 cm −2 respectively.
- Published
- 1999
20. Advanced excimer-laser annealing process for quasi single-crystal silicon thin-film devices
- Author
-
Masakiyo Matsumura and Chang-Ho Oh
- Subjects
Materials science ,Silicon ,business.industry ,Annealing (metallurgy) ,Transistor ,Metals and Alloys ,chemistry.chemical_element ,Silicon on insulator ,Surfaces and Interfaces ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,law.invention ,Grain growth ,chemistry ,law ,Thin-film transistor ,Materials Chemistry ,Optoelectronics ,Thin film ,Photonics ,business - Abstract
An advanced excimer-laser annealing method, named phase-modulated excimer-laser annealing method, has been reviewed for large-grain growth in Si thin-films. The laser-light intensity is modulated two-dimensionally on the Si film surface that triggers a lateral motion of the melt–solid interface, resulting in the lateral grain growth. The intensity distribution can be designed well by a phase-shift concept. Large grains were grown at pre-designed positions at 500°C, and are expected to possibly be aligned with less than 30 μm in pitch. The method seems attractive for high-performance and quasi single-crystal thin-film devices, which include thin-film transistors, silicon-on-insulator-based ULSIs, solar-cells and porous Si photonic devices.
- Published
- 1999
21. Hydrogen-induced abstraction mechanism of surface methyl groups in atomic-layer-epitaxy of germanium
- Author
-
Kimihiko Hosaka, Masakiyo Matsumura, and Satoshi Sugahara
- Subjects
Surface (mathematics) ,Hydrogen ,Chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Germanium ,Surfaces and Interfaces ,General Chemistry ,Activation energy ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Reaction rate ,chemistry.chemical_compound ,Mechanism (philosophy) ,Atomic layer epitaxy ,Physical chemistry ,Methyl group - Abstract
Reaction process has been studied for an atomic hydrogen-induced abstraction of methyl groups on the Ge surface. The reaction rate estimated from experiments had a very large activation energy and depended on a surface coverage of methyl groups; they are not expected for a `pure' Eley–Rideal mechanism. The process can be explained by the `modified' Eley–Rideal mechanism or the `precursor' mechanism based on two-dimensionally bound hydrogen atoms on the surface.
- Published
- 1998
22. Atomic-layer chemical-vapor-deposition of silicon dioxide films with an extremely low hydrogen content
- Author
-
Shigeru Imai, Kei-ichi Yamaguchi, Masakiyo Matsumura, Hidejiro Miki, Masashi Takemoto, and Naoto Ishitobi
- Subjects
Chemistry ,Silicon dioxide ,Inorganic chemistry ,Analytical chemistry ,General Physics and Astronomy ,Surfaces and Interfaces ,General Chemistry ,Surface finish ,Chemical vapor deposition ,Condensed Matter Physics ,Spectral line ,Surfaces, Coatings and Films ,Deposition rate ,Root mean square ,chemistry.chemical_compound ,Deposition (chemistry) ,Layer (electronics) - Abstract
We achieved the atomic-layer-deposition of SiO2 with an extremely low H content for the first time by using Si(NCO)4 and N(C2H5)3. The deposition rate was independent of the exposure times of both sources. The saturated deposition rate was about 1.2 A/cycle at 150°C. AFM observation revealed that the increase of roughness after 50 deposition cycles was only about 0.4 A in root mean square. The FT-IR spectra showed that the deposited film was SiO2 without Si–H, Si–OH or NCO bond.
- Published
- 1998
23. Application of Excimer-Laser Annealing to Amorphous, Poly-Crystal and Single-Crystal Silicon Thin-Film Transistors
- Author
-
Masakiyo Matsumura
- Subjects
Crystal ,Materials science ,Thin-film transistor ,business.industry ,Hybrid silicon laser ,Nanocrystalline silicon ,Optoelectronics ,Single crystal silicon ,Condensed Matter Physics ,business ,Excimer laser annealing ,Electronic, Optical and Magnetic Materials ,Amorphous solid - Published
- 1998
24. Gas-phase-reaction-controlled atomic-layer-epitaxy of silicon
- Author
-
Masakiyo Matsumura, Shinji Hoshino, Satoshi Sugahara, Keiji Ikeda, Shigeru Imai, and Eiji Hasunuma
- Subjects
Materials science ,Silicon ,Hydrogen ,Analytical chemistry ,chemistry.chemical_element ,Nanotechnology ,Surfaces and Interfaces ,Condensed Matter Physics ,Residence time (fluid dynamics) ,Chemical reaction ,Surfaces, Coatings and Films ,Gas phase ,chemistry ,Monolayer ,Atomic layer epitaxy ,Growth rate - Abstract
Atomic layer epitaxy of silicon has been studied by alternating exposures of atomic hydrogen and SiH2Cl2. An ideal growth rate of 1 monolayer per cycle has been achieved with a wide temperature window from 550 °C to 610 °C under long SiH2Cl2 residence time and high pressure conditions. These requirements seem to come from the generation of dense SiHCl, the desirable precursor, by gas-phase reaction of SiH2Cl2.
- Published
- 1998
25. Poly-Si/poly-SiC/sub x/ heterojunction thin-film transistors
- Author
-
Kwangsoo Choi and Masakiyo Matsumura
- Subjects
Electron mobility ,Materials science ,Silicon ,business.industry ,Wide-bandgap semiconductor ,chemistry.chemical_element ,Heterojunction ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,law.invention ,chemistry ,law ,Thin-film transistor ,Optoelectronics ,Electrical and Electronic Engineering ,Thin film ,Crystallization ,business - Abstract
We have proposed heterojunction thin-film transistors having a stacked structure of poly-crystal silicon-carbon (SiC/sub x/) and Si thin films, both of which are prepared by an excimer-laser crystallization method. A Si/SiC/sub x/ interface after intense excimer-laser irradiation for crystallization, was as abrupt as that of the as-deposited and amorphous structure. The device had a relatively high mobility of about 4 cm/sup 2//Vs and a sufficiently low leakage current of an order of 10/sup -14/ A//spl mu/m even under intense light illumination conditions.
- Published
- 1998
26. Modeling of germanium atomic-layer-epitaxy
- Author
-
Masakiyo Matsumura and Satoshi Sugahara
- Subjects
Hydrogen ,Chemistry ,Thermal desorption ,General Physics and Astronomy ,chemistry.chemical_element ,Germanium ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Chemical reaction ,Surfaces, Coatings and Films ,Adsorption ,Desorption ,Monolayer ,Atomic layer epitaxy ,Physical chemistry - Abstract
Atomic-layer-epitaxy (ALE) of germanium has been analyzed by a kinetic model and a thermodynamic model. Chlorogermanes are found to be unsuitable since they cannot satisfy the self-limiting adsorption condition due to quick thermal desorption of HCl from the surface. On the other hand, the ideal growth rate of one monolayer per cycle is expected for dimethylgermane. This is because there exists no recombinative desorption reaction between surface methyl groups and H that will break the self-limiting adsorption condition. It has also been confirmed, from thermodynamic considerations, that the elemental chemical reactions used in this ALE, i.e., self-limiting adsorption and reduction of surface methyl groups by atomic hydrogen, are spontaneous.
- Published
- 1997
27. Atomic layer etching of germanium
- Author
-
Shigeru Imai, Keiji Ikeda, and Masakiyo Matsumura
- Subjects
Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Germanium ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Isotropic etching ,Surfaces, Coatings and Films ,chemistry ,Etching (microfabrication) ,Monolayer ,Surface roughness ,Dry etching ,Reactive-ion etching ,Layer (electronics) - Abstract
Atomic layer etching of Ge has been investigated experimentally based on the surface chemistry that Cl can adsorb on the clean Ge surface at room temperature and desorb thermally as GeCl 2 at high temperatures. The ideal etching rate of one monolayer per cycle has been achieved. The critical Cl 2 dosage for the saturated etching rate was about 7.2×10 6 L. Increase of the surface roughness after etching of 100 cycles was about 3.5 monolayers.
- Published
- 1997
28. Modeling of silicon atomic-layer-epitaxy
- Author
-
Satoshi Sugahara, Sigeru Imai, Eiji Hasunuma, and Masakiyo Matsumura
- Subjects
Kinetic model ,Hydrogen ,Silicon ,General Physics and Astronomy ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Limiting ,Surface reaction ,Condensed Matter Physics ,Surfaces, Coatings and Films ,chemistry ,Monolayer ,Atomic layer epitaxy ,Physical chemistry ,Growth rate - Abstract
A kinetic model has been presented for atomic layer epitaxy of Si using cyclic exposures of SiH 2 Cl 2 and atomic hydrogen. This model is based on the surface reaction of adsorbates formed by gas-phase reaction of SiH 2 Cl 2 . The ideal growth rate of one monolayer per cycle is achieved only when the dominant precursor is SiHCl. Limiting factors of the ALE window are also discussed.
- Published
- 1996
29. Ideal monolayer adsorption of germanium on Si(100) surface
- Author
-
Sigeru Imai, Takuya Kitamura, Yasutaka Uchida, Masakiyo Matsumura, and Satoshi Sugahara
- Subjects
Surface (mathematics) ,Ideal (set theory) ,Silicon ,Chemistry ,Inorganic chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Germanium ,Surfaces and Interfaces ,General Chemistry ,Molecular precursor ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Adsorption ,Chemical engineering ,Monolayer - Abstract
Self-limiting monolayer adsorption of Ge has been demonstrated on Si(100) at 520°C using dimethylgermane as a self-limiting molecular precursor. This opens a way for hetero-ALE of Ge on the Si surface.
- Published
- 1996
30. Excimer-laser crystallized poly-Si TFT's with transparent gate
- Author
-
Masakiyo Matsumura and Chang-Dong Kim
- Subjects
Electron mobility ,Materials science ,Liquid-crystal display ,Excimer laser ,Silicon ,business.industry ,medicine.medical_treatment ,chemistry.chemical_element ,Substrate (electronics) ,Oxide thin-film transistor ,Electronic, Optical and Magnetic Materials ,Active matrix ,law.invention ,chemistry ,Thin-film transistor ,law ,medicine ,Optoelectronics ,Electrical and Electronic Engineering ,business - Abstract
A new poly-crystal silicon thin-film transistor (poly-Si TFT) with a transparent bottom-gate electrode has been fabricated by XeF excimer-laser light irradiation from the glass substrate side. Compared with poly-Si TFTs made by XeF or ArF excimer-laser light irradiation to the top Si surface, the new TFT shows a higher electron mobility of about 100 cm/sup 2//Vs, independent of the Si film thickness. Therefore, poly-Si driver TFTs and amorphous-silicon (a-Si) TFTs for the matrix can be formed with the same channel-etch type bottom-gate structure simultaneously on the same glass substrate by using the same starting materials. This is expected to open the way for making driver monolithic and active matrix liquid crystal displays.
- Published
- 1996
31. Application of Excimer Laser to Display Production Technology
- Author
-
Masakiyo Matsumura
- Subjects
Materials science ,Excimer laser ,business.industry ,medicine.medical_treatment ,medicine ,Production (economics) ,Optoelectronics ,business - Published
- 1996
32. Atomic hydrogen-assisted ALE of germanium
- Author
-
Satoshi Sugahara, Takuya Kitamura, Masaru Kadoshima, Masakiyo Matsumura, and Sigeru Imai
- Subjects
chemistry.chemical_classification ,Chemical substance ,Hydrogen ,Stereochemistry ,Chemistry ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Crystal growth ,Germanium ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Epitaxy ,Surfaces, Coatings and Films ,Hydrocarbon ,Monolayer ,Atomic layer epitaxy - Abstract
Atomic layer epitaxy of germanium has been demonstrated successfully by alternating exposures of atomic hydrogen, which acts as a reactant for extracting hydrocarbon from the surface, and of dimethylgermane as a self-limiting molecular precursor. The ideal growth rate of one monolayer per cycle has been achieved with a wide ALE temperature window between 420°C and 528°C.
- Published
- 1995
33. New substances for atomic-layer deposition of silicon dioxide
- Author
-
S. Morishita, Masakiyo Matsumura, Koh Ichi Usami, and W. Gasser
- Subjects
biology ,Chemistry ,Silicon dioxide ,Semiconductor materials ,Inorganic chemistry ,Condensed Matter Physics ,biology.organism_classification ,Silane ,Isocyanate ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,Atomic layer deposition ,Materials Chemistry ,Ceramics and Composites ,Chemical preparation ,Tetra ,Deposition (phase transition) - Abstract
Based on the first result of the layer-by-layer deposition of silicon dioxide films by a cyclic exposure of water and tetra isocyanate silane, Si(NCO) 4 , new isocyanate compounds preferable to Si(NCO) 4 have been proposed for ideal layer-by-layer deposition characteristics. Preliminary results are also presented for one of the substances.
- Published
- 1995
34. Atomic Layer Epitaxy of Silicon
- Author
-
Toshio Iizuka, Masakiyo Matsumura, Satoru Takagi, Osamu Sugiura, and Shigeru Imai
- Subjects
Materials science ,Silicon ,Trisilane ,Mechanical Engineering ,Analytical chemistry ,Dichlorosilane ,chemistry.chemical_element ,Substrate (electronics) ,Industrial and Manufacturing Engineering ,chemistry.chemical_compound ,Adsorption ,chemistry ,Mechanics of Materials ,Desorption ,Monolayer ,Atomic layer epitaxy ,General Materials Science - Abstract
Two methods are proposed and demonstrated successfully for low temperature atomic layer epitaxy (ALE) of Si, where H atoms play essential roles. The first method is the use of H as a self-limiting factor. Trisilane (Si3H8) was used as source gas and the substrate temperature was modulated in order to alternate steps in an ALE cycle. When the temperature was less than 380°C in the adsorption step and more than 520°C in the desorption step, respectively, the grown layer thickness per cycle was 0.8 ML/cycle. The second method is the use of atomic H as an active reducer of a self-limiting factor. A clean surface was exposed to dichlorosilane (SiH2Cl2) as source gas to grow an Si monolayer covered with CI. Next, atomic H was injected to reduce CI from the surface. An ideal monolayer growth was obtained with the substrate temperature over 540°C.
- Published
- 1995
35. Atomic layer epitaxy of germanium
- Author
-
Masakiyo Matsumura, Takuya Kitamura, Satoshi Sugahara, and Shigeru Imai
- Subjects
Hydrogen ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Germanium ,Surfaces and Interfaces ,General Chemistry ,Chemical vapor deposition ,Substrate (electronics) ,Condensed Matter Physics ,Surfaces, Coatings and Films ,chemistry ,Desorption ,Phase (matter) ,Monolayer ,Atomic layer epitaxy - Abstract
Novel atomic layer epitaxy (ALE) methods have been proposed for Ge, where the elemental kinetics of the chemical vapor deposition method are divided into two sequential phases, i.e., a monolayer adsorption phase and a subsequent desorption phase for the surface-terminating species. Ge-ALE has been achieved, for the first time, with an ideal growth rate of one monolayer per cycle, under constant substrate temperature conditions. The detailed ALE method and growth characteristics have been presented. Furthermore, atomic hydrogen exposure is shown to be effective for widening the Ge-ALE window.
- Published
- 1994
36. Hydrogen atom assisted ALE of silicon
- Author
-
Shigeru Imai and Masakiyo Matsumura
- Subjects
Silicon ,Analytical chemistry ,General Physics and Astronomy ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Hydrogen atom ,Substrate (electronics) ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Adsorption ,chemistry ,Desorption ,Monolayer ,Irradiation ,Layer (electronics) - Abstract
Two ALE methods of Si are successfully demonstrated, where H atoms play an essential role. In the first method, H atoms are used as self-limiting species over the grown layer. Si3H8 was used as source gas and the substrate temperature was modulated in order to switch two steps, i.e. an adsorption step and a desorption step, in an ALE cycle. When the temperature was lower than 380°C in the adsorption step and higher than 520°C in the desorption step, the grown layer thickness per cycle was saturated at 0.8 ML/cycle, closer to the ideal value than in the SiH4 or Si2H6 cases. In the second method, atomic H is used as an active reducer of the self-limiting species. SiH2Cl2 as source gas and atomic H were irradiated to the surface, alternately. An ideal monolayer growth per cycle was obtained with the substrate temperature over 540°C, much lower than in the case of the molecular H2 reducer.
- Published
- 1994
37. Quasi-monolayer deposition of silicon dioxide
- Author
-
Yasutaka Uchida, Masakiyo Matsumura, and Werner Gasser
- Subjects
Auger electron spectroscopy ,Silicon ,Chemistry ,Layer by layer ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Infrared spectroscopy ,Surfaces and Interfaces ,Silane ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,Monolayer ,Materials Chemistry ,Thin film - Abstract
SiO2 films were deposited layer by layer from a new silicon source gas, i.e. tetra-iso-cyanate-silane (Si(NCO)4). An average growth rate of about 0.17 nm per cycle was achieved by a cyclic process of alternating reaction of the substrate surface with Si(NCO)4 and H2O respectively. The detailed deposition characteristics together with chemical and physical properties of the deposited film were evaluated with ellipsometry, Fourier transform IR spectroscopy, X-ray photoelectron spectroscopy and Auger electron spectroscopy.
- Published
- 1994
38. Effects of excimer-laser annealing on low-temperature-deposited silicon-nitride film
- Author
-
Masakiyo Matsumura, Yasutaka Uchida, and Kazuhiro Shimizu
- Subjects
Materials science ,Silicon ,business.industry ,Annealing (metallurgy) ,Transistor ,General Physics and Astronomy ,chemistry.chemical_element ,Surfaces and Interfaces ,General Chemistry ,Condensed Matter Physics ,Surfaces, Coatings and Films ,law.invention ,chemistry.chemical_compound ,Optics ,Silicon nitride ,chemistry ,Chemical bond ,X-ray photoelectron spectroscopy ,law ,Optoelectronics ,Irradiation ,business ,Excimer laser annealing - Abstract
We have found that an undesirable SiNH component is reduced drastically from the low-temperature-deposited SiN surface by intense ArF excimer-laser irradiation on the low-temperature-deposited SiN film. This pre-annealing of the SiN film is very effective in forming an abrupt Si/SiN interface, and thus plays a very important role in high-performance excimer-laser-crystallized poly-Si/SiN thin-film transistors aiming at high-quality liquid-crystal displays. Annealing characteristics are also presented for the various SiN film thickness and for both the ArF and KrF excimer-laser lights.
- Published
- 1994
39. Amorphous-silicon distributed-threshold voltage transistors with self-aligned poly-silicon sources and drains
- Author
-
Masakiyo Matsumura and Chang-Dong Kim
- Subjects
Amorphous silicon ,Materials science ,Silicon ,business.industry ,Transistor ,chemistry.chemical_element ,Microstructure ,Electronic, Optical and Magnetic Materials ,law.invention ,Threshold voltage ,chemistry.chemical_compound ,chemistry ,law ,Electronic engineering ,Optoelectronics ,Electrical and Electronic Engineering ,Photomask ,business ,Communication channel - Abstract
A microstructure has been introduced into the channel of amorphous-silicon thin-film transistors with poly-silicon sources and drains. A slant-photolithography method was introduced for fabricating this device without additional photomasks. The off-characteristics have been improved without sacrificing originally good on-characteristics. Temperature dependence is also discussed for the transistor characteristics. >
- Published
- 1994
40. Atomic layer epitaxy of Si using atomic H
- Author
-
Shigeru Imai, Osamu Sugiura, Masakiyo Matsumura, and Toshio Iizuka
- Subjects
Reducer ,Chemistry ,Metals and Alloys ,Analytical chemistry ,Surfaces and Interfaces ,Substrate (electronics) ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Monolayer ,Materials Chemistry ,Atomic layer epitaxy ,Reactivity (chemistry) ,Growth rate ,Deposition (law) - Abstract
Atomic H is proposed for the reducer gas in the atomic layer epitaxy (ALE) of Si. Its high reactivity makes it possible to remove surface-terminating adsorbates, which cause the self-limitation of unwanted successive deposition of Si compounds, at low temperature. The ALE growth was attempted by the alternating exposure of the Si(111) substrate to SiH 2 Cl 2 and H. Ideal monolayer growth was obtained and the growth rate was independent of the gas volumes and the substrate temperature. The lower ALE limit of the substrate temperature was 540 °C, about 250 °C lower than the case of H 2 as the reducer gas.
- Published
- 1993
41. High-mobility poly-Si thin-film transistors fabricated by a novel excimer laser crystallization method
- Author
-
Kazuhiro Shimizu, Osamu Sugiura, and Masakiyo Matsumura
- Subjects
Materials science ,business.industry ,Transistor ,Substrate (electronics) ,Electron ,Laser ,Grain size ,Electronic, Optical and Magnetic Materials ,law.invention ,Thin-film transistor ,law ,Electronic engineering ,Optoelectronics ,Irradiation ,Electrical and Electronic Engineering ,business ,Layer (electronics) - Abstract
High-mobility poly-Si thin-film transistors (TFTs) were fabricated by a novel excimer laser crystallization method based on dual-beam irradiation. The new method can reduce the solidification velocity of the top Si layer by heating the bottom Si layer of the Si/SiO/sub 2//Si/glass substrate structure by means of laser irradiation not only from the front side but also from the back side. The grain size of poly-Si film was enlarged up to 2 mu m. The field-effect mobilities of the TFT exceeded 380 cm/sup 2//V-s for electrons and 100 cm/sup 2//V-s for holes. >
- Published
- 1993
42. The effects of post-hydrogenation on amorphous-silicon thin-film transistors
- Author
-
Hiroshi Kanoh, Masakiyo Matsumura, Osamu Sugiura, Koh-ichi Usami, and Byung-Chul Ahn
- Subjects
Amorphous silicon ,Materials science ,Hydrogen ,Computer Networks and Communications ,business.industry ,Transistor ,General Physics and Astronomy ,chemistry.chemical_element ,Transit time ,Chemical vapor deposition ,Threshold voltage ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Thin-film transistor ,Electronic engineering ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Critical condition - Abstract
The characteristics of amorphous silicon thin-film transistors fabricated by chemical vapor deposition method is discussed in detail in conjunction with posthydrogenation. As the hydrogenation around an active interface starts, the transistor performance is abruptly improved and then does not change with further hydrogenation. A critical condition for hydrogenation for such an abrupt improvement may be accounted for based on a simple formula using a transit time of hydrogen atoms. A desirable thickness of amorphous silicon films for high performance TFT is thicker than 100 nm. In addition, it is recommended that hydrogenation is to be made at a temperature as low as possible as long as it can be possible.
- Published
- 1993
43. A proposed single grain-boundary thin-film transistor
- Author
-
Chang-Ho Oh and Masakiyo Matsumura
- Subjects
Maximum temperature ,Electron mobility ,Materials science ,Transistor ,Analytical chemistry ,Electronic, Optical and Magnetic Materials ,law.invention ,Crystallinity ,law ,Thin-film transistor ,Subthreshold swing ,Electronic engineering ,Grain boundary ,Electrical and Electronic Engineering ,Crystallization - Abstract
A new Si thin-film transistor (TFT) has been proposed where only one grain-boundary exists at the center of channel, and the source and drain are within single grains with good crystallinity. The device fabricated by an excimer-laser crystallization method at the maximum temperature of 500/spl deg/C, had the on-off current ratio /spl cong/10/sup 6/, the field-effect mobility /spl cong/330 cm/sup 2//Vs and the subthreshold swing /spl cong/1.1 V/dec, respectively, For the device processed at 800/spl deg/C, they are >10/sup 6/, >450 cm/sup 2//Vs and /spl cong/0.51 V/dec, respectively.
- Published
- 2001
44. Characteristics of amorphous-silicon distributed-threshold voltage transistors formed by ion implantation
- Author
-
Osamu Sugiura, T. Satoh, and Masakiyo Matsumura
- Subjects
Amorphous silicon ,Materials science ,Silicon ,business.industry ,Transistor ,chemistry.chemical_element ,Hardware_PERFORMANCEANDRELIABILITY ,Overdrive voltage ,Electronic, Optical and Magnetic Materials ,law.invention ,Threshold voltage ,chemistry.chemical_compound ,Ion implantation ,chemistry ,Hardware_GENERAL ,law ,Thin-film transistor ,Hardware_INTEGRATEDCIRCUITS ,Electronic engineering ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Voltage - Abstract
Hot ion-implantation has been applied to threshold voltage control of amorphous-silicon thin-film transistors. A threshold voltage shift as large as 13 V has been achieved without deterioration of the field-effect mobility. The technique was also used to form distributed-threshold voltage transistors which have a microstructure inside the channel. It was verified that the off-characteristics were greatly improved. >
- Published
- 1992
45. LOW-TEMPERATURE CHEMICAL-VAPOR-DEPOSITION OF SILICON NITRIDE
- Author
-
T. Hattori, Hiroshi Kanoh, S. Fujioka, Masakiyo Matsumura, Y. Aramaki, and Osamu Sugiura
- Subjects
chemistry.chemical_compound ,Materials science ,Silicon nitride ,chemistry ,[PHYS.HIST]Physics [physics]/Physics archives ,0103 physical sciences ,General Physics and Astronomy ,Nanotechnology ,Chemical vapor deposition ,7. Clean energy ,01 natural sciences ,010305 fluids & plasmas - Abstract
Low-temperature CVD method has been investigated for silicon-nitride films by using higher silanes and hydrazine aiming at thin-film transistor application. The deposition temperature has been reduced to as low as 350°C, i.e., by about 400°C lower than the typical temperature. Atomic N/Si ratio was more than 4/3, i.e., the film was stoichiometric SiN, and hydrogen content was as high as 20 atomic%. Breakdown field strength, specific resistivity and MIS interface state density were about 6MV/cm, 6x1015 Ωcm and 1x1011cm-2eV-1, respectively.
- Published
- 1991
46. Excimer-Laser Growth of Si Large-Grain Arrays
- Author
-
Masakiyo Matsumura
- Subjects
Crystal ,Amorphous silicon ,chemistry.chemical_compound ,Materials science ,Liquid-crystal display ,Excimer laser ,chemistry ,law ,Thin-film transistor ,medicine.medical_treatment ,medicine ,Engineering physics ,law.invention - Abstract
Amorphous silicon (a-Si) Thin Film Transistors (TFT) will continue to play an important role in large-area liquid crystal displays (LCD), however, there is also a strong demand for ultra-high performance TFTs aimed at intelligent small (or medium) size displays. For this reason, “Crystal Si on glass” has become an increasingly attractive solution. This paper reviews recent work performed at ALTEDEC (Advanced LCD Technologies Development Center Co., Ltd, with regard to growing an array of large Si grains at low temperature. The results obtained so far indicate that satisfactory progress has been made towards the achievement of this goal.
- Published
- 2004
47. Excimer-laser-produced two-dimensional arrays of large Si grains
- Author
-
Masakiyo Matsumura
- Subjects
Materials science ,Excimer laser ,business.industry ,medicine.medical_treatment ,Crystal growth ,Laser ,law.invention ,Grain growth ,Crystallinity ,Light intensity ,Optics ,Thin-film transistor ,law ,medicine ,Optoelectronics ,business ,Layer (electronics) - Abstract
Experimental and theoretical results are reviewed for an excimer-laser-based Si large-grain growth method aiming at a 'system-on-panel' technology. Temperature in the Si thin layer should have a gentle slope along the one direction for growing large grains and should have a steep dip along the other direction for controlling their positions. In order to produce such a temperature distribution using an excimer- laser light pulse, phase-shifter patterns that generate the 2D distribution of the light intensity on the sample surface by Fresnel effects should be independently optimized for both directions. The sample should be of a stacked structure of the heat storage layer, the Si layer and the underlayer with low heat diffusing power. The Si layer thickness is a critical parameter for long grain growth, and should be very thin under the condition of the thick heat storage layer. The growth large grains seem to have excellent crystallinity although experimental data is not sufficient.
- Published
- 2001
48. Advanced Excimer-Laser Recrystallization Technology for Crystal-Si Thin-Film Devices
- Author
-
Masakiyo Matsumura
- Subjects
Materials science ,Excimer laser ,Annealing (metallurgy) ,business.industry ,medicine.medical_treatment ,Recrystallization (metallurgy) ,Grain growth ,Thermal conductivity ,medicine ,Optoelectronics ,Thin film ,business ,Porosity ,Quartz - Abstract
This paper reviews an excimer-laser annealing (ELA) method of Si thin-films on glass studied in the Tokyo Institute of Technology, aiming at position-controlled ultra-large grain growth with high packing density by a single shot irradiation of a laser-light pulse. Key concepts are (I) 2-D modulation of the laser light intensity on the sample surface, (II) reduction of the heat removal rate from the molten Si thin layer of high temperature, and (III) enlargement of the effective specific-heat while keeping the effective thermal-conductivity low for annealed layers. There were two possible solutions for the condition (I). The first solution is of an application of a cross-coupled phase-shifter formed on a transparent quartz plate. The second solution is of a half-tone phase-modulation method (PAMELA method) using semi-transparent thin films on quartz substrate with phase-shifter. The condition (II) is satisfied by changing the SiO2 underlayer to the porous or organic silica underlayer for reducing vertical heat flow flux to the cool underlayer, and by thinning the Si layer for reducing heat flow flux along the highly conductive Si layer. The condition (III) is satisfied, by the SiON capping layer for a KrF excimer laser, and by the SiOC capping layer for a XeCl excimer laser, since they have a reasonable light absorption coefficient, low thermal conductivity, large specific-heat and sufficient heat tolerance.
- Published
- 2001
49. Low‐temperature chemical vapor deposition of boron‐nitride films using hydrogen azide
- Author
-
Masakiyo Matsumura, Osamu Sugiura, and Ryoichi Ishihara
- Subjects
Materials science ,Physics and Astronomy (miscellaneous) ,Hydrogen ,Silicon ,Inorganic chemistry ,chemistry.chemical_element ,Substrate (electronics) ,Chemical vapor deposition ,Amorphous solid ,chemistry.chemical_compound ,chemistry ,Boron nitride ,Stoichiometry ,Diborane - Abstract
Stoichiometric boron‐nitride films have been successfully deposited at temperatures as low as 400 °C by chemical vapor deposition using diborane (B2H6) and hydrogen azide (HN3). The film deposited on the silicon substrate at 475 °C was amorphous and contained hydrogen atoms with a density of 1.3×1022 cm−3. The breakdown field strength and the low‐field resistivity were 2.8 MV/cm and 1015 Ω cm, respectively. The optical and low‐frequency dielectric constants were 3.6 and 4.0, respectively. Metal‐insulator‐metal device equipped with this film showed steep current‐voltage characteristics.
- Published
- 1992
50. Single-Shot Excimer-Laser Crystallization of an Ultra-Large Si Thin-Film Disk
- Author
-
Mitsuru Nakata, Masakiyo Matsumura, and Chang-Ho Oh
- Subjects
Excimer laser crystallization ,Materials science ,Thin-film transistor ,business.industry ,Single shot ,Optoelectronics ,Thin film ,business ,Intensity (heat transfer) ,Pulse (physics) - Abstract
An excimer-laser-induced large-grain growth method has been proposed which utilizes non-uniform heat diffusion along the Si thin-film and also along the underlayer. A single-shot of KrF excimer-laser light pulse with uniform intensity could crystallize a circularly pre-patterned Si thin-film of 20νm in diameter, much larger than TFT feature size in present AM-LCD panels.
- Published
- 2000
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.