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Plasma and electrical characteristics of an internal-type inductively coupled plasma source with a Ni–Zn ferrite module installed near the antenna were investigated for different rf power frequencies of 2 and 13.56 MHz. Due to the lower heating of the Ni–Zn ferrite module on the antenna for the operation at 2 MHz compared to the operation at 13.56 MHz, higher plasma density and lower rf rms antenna voltage were resulted for the operation at 2 MHz in addition to more stable plasma characteristics. By the application of 500 W of rf power to the source, a high plasma density of 8 × 1011 cm−3 which is about four times higher than that with 13.56 MHz could be obtained at the pressure of 10 mTorr Ar. When photoresist etch uniformity was measured for the operation with 2 MHz by etching photoresist on a 300 mm diameter substrate using 10 mTorr Ar/O2 (9:1) mixture, the etch uniformity of about 5.5% could be obtained.

An internal-type linear inductive antenna, which is referred to as “double comb-type antenna”, was used as a large-area inductively coupled plasma (ICP) source with a substrate area of 2,300 mm × 2,000 mm. The characteristics of the ICP source were investigated for potential applications to flat panel display (FPD) processing. The source showed higher power transfer efficiency at higher RF power and higher operating pressures. The power transfer efficiency was approximately 88.1% at 9 kW of RF power and a pressure of 20 mTorr Ar. This source showed increasing plasma density and improved plasma uniformity with increasing RF power at a given operating pressure. A plasma density >1.5 × 1011/cm3 and a plasma uniformity of approximately 11% was obtained at 9 kW of RF power and 15 mTor Ar using this internal ICP source, which is applicable to FPD processing.

SiO 2 -like thin films were deposited at a low temperature (

Nano/microcrystalline silicon thin films were deposited using an internal-type, inductively coupled, plasma-chemical vapor deposition (ICP-CVD) at room temperature by varying the bias power to the substrate. The structural characteristics of the deposited thin film were investigated. The deposition rate was increased by the application of a small RF bias power of 30 W (12.56 MHz), but was then decreased as the bias power was increased above 30 W. In addition, the application of bias power generally increased the residual compressive stress, which was attributed to the increased defect formation in the thin film due to the formation of interstitial atoms. The crystalline volume fraction was also decreased with increasing bias power. However, in the low bias power range of 0–60 W, the compressive stress in the deposited thin film was in the range of − 34 to − 77 MPa, which was lower than the residual stress in the range of − 150 to − 1050 MPa that is observed for the nano/microcrystalline silicon thin films deposited by capacitively coupled plasma.

Using an internal inductively coupled plasma (ICP)-type-plasma enhanced vapor deposition system, microcrystalline silicon thin films were deposited as a function of H 2 /SiH 4 gas ratio at 180 °C. Especially, the effects of deposition with/without an initial thin silicon layer formed with a very high hydrogen percentage on the microstructure of the deposited silicon thin film were investigated. The deposited silicon thin film showed higher crystallization percentage at the higher hydrogen percentage in H 2 /SiH 4 due to the high ratio of H/SiH in the plasma. At the same gas mixture of H 2 /SiH 4 , the deposition of silicon thin film after the formation of an initial silicon layer with a high hydrogen percentage on the glass substrate increased the crystallization percentage from 3 to 14%. The initial silicon layer deposited with a high hydrogen percentage showed a nanocrystalline grain structure; therefore, the nanocrystalline structure in the initial silicon layer appeared to act as a nucleation site for the growth of microcrystalline silicon thin films. Using the internal ICP-PECVD, the microcrystalline silicon having about 87% of crystallization could be deposited on the glass substrate at 180 °C with the 90% of hydrogen dilution percentage and with the thin initial silicon layer.

This paper reports the favorable performance of a top-emitting organic light-emitting diode (TEOLED) using a Ba/Au/indium tin oxide (ITO) cathode. A cathode with a Ba layer and a long skin depth of 44.1 nm not only prevented damage to the underlying organic layers from ion bombardment during ITO sputtering, but also improved the light out-coupling of devices by increasing the transmittance. With increasing Ba thickness, the turn-on voltage and leakage current of the devices were lower than of those without Ba. The Ba layer in the cathode enhanced the optical characteristics of the devices by the balanced carrier injection.

Plasma characteristics and electrical parameters of an internal linear inductively coupled plasma (ICP) source with a U-type antenna with/without a Ni–Zn ferromagnetic material installed near the antenna were investigated. The application of the ferromagnetic material to the antenna increased the plasma density, improved the plasma uniformity, lowered the antenna voltage, and increased the stability of the plasma during the operation. For the U-type ferromagnetic enhanced internal linear ICP source, a high density plasma on the order of 4.5×1011 cm-3 which is about three higher than that obtained for the source without the ferromagnetic material could be obtained at the pressure of 10 mTorr Ar and at the RF power of 600 W at 13.56 MHz.

To improve the field emission properties of screen printed carbon nanotube (CNT) films, an Ar neutral beam was used as one of the surface treatment techniques and the CNT field emission characteristics after the treatment were compared with those after Ar ion beam treatment. The Ar neutral beam treatment enhanced the field emission properties of the CNTs and by decreasing the turn-on field and by increasing emission sites. When the field emission properties were measured after the treatment for 10 s with an energy of 100 eV, the turn-on field decreased from 1.7 to 0.9 V/μm while that after the ion beam treatment increased from 1.7 to 2.8 V/μm showing damage of exposed CNTs due to the intensive bombardment by the positive ions in the beam. The neutral beam treatment appeared to expose more CNT field emitters from the CNT paste without cutting or severely damaging the already exposed long CNT emitters because there were no charged particles in the beam.

Characteristics of atomic layer etching of (100) GaAs and (111) GaAs have been investigated using Ne neutral beam and Cl2 gas. By using a Ne neutral beam dose and a Cl2 gas pressure higher than critical values of 3.03 × 1016 atoms/cm2·cycle and 0.4 mTorr, respectively, steady state etch rates of 1.41 A/cycle for (100) GaAs and 1.63 A/cycle for (111) GaAs which correspond to the etch rate of one atomic layer/cycle could be obtained. At the monolayer etching condition, the roughness of the GaAs surface was remaining similar to that of the unetched GaAs surface. In addition, the GaAs etched by the atomic layer etching showed the surface composition similar to that before the etching while the GaAs etched by a conventional reactive ion etching such as an inductively coupled plasma etching showed significant change in the surface composition.

On the surfaces of GaN-based light-emitting diodes (LEDs) having an n-side-up vertical electrode structure formed by the laser lift-off, various shapes of photoresist-patterned surface textures were formed by inductively coupled plasma etching and their effect on the light emission efficiencies was investigated. By the formation of various shapes of surface textures, the light output efficiency was increased from 37% to 45% compared to that without surface textures. The increase of light output efficiency was related to the increase of sidewall scattering, the decrease of reflected loss, and the decrease of cavity wall effect that occurs for the vertical LEDs by the increase of sidewall surface area.

Si x Ny thin films were deposited by PECVD using SiH 4 /NH 3 /Ar gases and by biasing the substrate at -50 V as a function of the ratio of R (R-NH3/(NH3+SiH4)) at a low temperature (

Top-emitting organic light-emitting diodes (TEOLEDs) with a thin semitransparent conducting cathode (STCC) of Ba/Al/ITO were fabricated and their electrical/optical characteristics were investigated. At the wavelength of 519 nm, optical properties of STCC of the Ba (5 nm)/Al (10 nm)/ITO (100 nm) structure showed the transmittance of 75% and the reflectance of 13%. The light out-coupling properties of the TEOLED, which is consisted of glass/Ag (100 nm)/ITO (125 nm)/4,4′,4″-tris[2-naphthylphenyl-1-phenylamino]triphenylamine (2-TNATA, 30 nm)/4,4′-bis[ N -(1-napthyl)- N -phenyl-amino]-biphenyl (NPB, 18 nm)/tris(8-quinolinolato)aluminum (III) (Alq 3 , 62 nm)/Ba ( x nm, x = 15, 10, and 5 nm)/Al (10 nm)/ITO (100 nm), was increased as the deposition thickness of Ba is reduced. This driving performance of the devices could be interpreted on the base of carrier injection barrier by Fowler–Nordheim tunneling theory as well as the optical properties of the cathode. A constant barrier height of 0.4 eV was obtained for all the devices regardless of the cathode structure composed of Ba ( x nm)/Al (10 nm)/ITO (100 nm), which indicates the electron-only devices where the injection barrier is at the ITO/2-TNATA interface.

Using a large area internal-type inductively coupled plasma (ICP) source called “multiple U-type ICP source” having the size of 1020×830mm2, the electrical properties of the antennas and the dissociation characteristics were investigated as a function of rf power using pure SiH4 and their influence on the deposited silicon films was studied. With increasing rf power, the plasma mode has changed from capacitively coupled plasma (E mode) to inductively coupled plasma (H mode), and the change of plasma mode increased the ratios of HFulcher*∕SiH* and Si*∕SiH* by changing the electron energy distribution function. In addition, the increase in HFulcher*∕SiH* changed the microstructure of a silicon thin film deposited on glass substrates from amorphous to microcrystalline. At the high rf power regime of 4000W, a silicon films having the crystalline volume fraction of 53% with optical band gap (Tauc’) of about 2.1eV and dark conductivity of 2.4×10−5Ω−1cm−1 could be obtained at 20mTorr of SiH4 [70SCCM (SCCM denote...

Top-emitting organic light-emitting diodes (TEOLEDs) with a thin semitransparent conducting cathode (STCC) of Ba∕Ag/indium tin oxide (ITO) were fabricated and their electric/optical characteristics were investigated. At the wavelength of 520nm, optical properties of STCC of the Ba(3nm)∕Ag(15nm)/ITO (100nm) structure showed the transmittance of 63% and the reflectance of 37%. The light out-coupling properties of the TEOLED, which is composed of glass/Ag(150nm)/ITO (130nm)∕4,4′,4″-tris[2-naphthylphenyl-1-phenylamino]triphenylamine (2-TNATA, 30nm)/4,4′-bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (18nm)/tris(8-quinolinolato)aluminum (III) (62nm)∕Ba (xnm,x=3,2,and1nm)∕Ag(15nm)/ITO (100nm), was increased as the deposition thickness of Ba is increased. This driving performance of the devices could be interpreted on the base of carrier injection barrier by measuring built-in voltage as well as both the optical properties and electric properties of the cathode. The optical properties (e.g., transmittance and reflec...

White top-emitting organic light-emitting diodes (TEOLEDs) composed of one doped emissive layer which emits two-wavelength light though the radiative recombination were fabricated. As the emissive layer, 4,4-bis(2,2-diphenylethen-1-yl)biphenyl (DPVBi) was used as the host material and 4-(dicyanomethylene)-2- tert -butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) was added as the dopant material. By optimizing the DCJTB concentration (1.2%) and the thickness of the DPVBi layer (30 nm), the intensity ratio of the two wavelengths could be adjusted for balanced white light emission. By using the device composed of glass/Ag (100 nm)/ITO (90 nm)/2-TNATA (60 nm)/NPB (15 nm)/DPVBi:DCJTB (1.2%, 30 nm)/Alq 3 (20 nm)/Li (1.0 nm)/Al (2.0 nm)/Ag (20 nm)/ITO (63 nm)/SiO 2 (42 nm), the Commission Internationale d'Eclairage (CIE) chromaticity coordinate of (0.32, 0.34) close to the ideal white color CIE coordinate could be obtained at 100 cd/m 2 .

The characteristics of a large-size internal-type inductively coupled plasma (ICP) source having a \double-comb-type" antenna have been investigated for the processing of a large-area at-panel display substrate having a size of 2,300 mm 2,000 mm, and its characteristics were compared with those for an ICP source having a \serpentine-type" antenna. The ICP source with the \double-comb-type" antenna showed a lower impedance, a higher plasma uniformity, and a higher plasma density compared to the ICP source with the \serpentine-type" antenna. The measured plasma density and uniformity of the ICP source with the \double-comb-type" antenna were higher than 8.5 1010/cm3 and lower than 14 %, respectively, at a 10 kW rf power and 15 mTorr of Ar. The etch uniformity of the photoresist within the substrate was about 12.5 % at a 8 kW rf power and 15 mTorr Ar/O2 (7 : 3).

The electrical and the plasma properties of an internal linear inductively coupled plasma (ICP) source with/without a C-shaped Ni-Zn ferromagnetic module installed near the inductive antenna were investigated. The installation of the ferromagnetic module decreased the voltage and the current of the antenna at a given power while the phase angle between the voltage and the current was decreased. Therefore, the load resistance and the power transfer e ciency were increased at the same rf power for the ICP source with the ferromagnetic module. At a rf power of 800 W and 5 mTorr, the installation of the ferromagnetic material increased the plasma density from 2.9 1011/cm3 to 3.5 1011/cm3 while decreasing the plasma potential and the electron temperature slightly.

It is known that single-walled carbon nanotubes (SWCNTs) can be functionalized by fluorine gas. Here, we report neutralized fluorine radical detection using a matted sheet of SWCNTs, prepared by alternating current dielectrophoresis. Upon exposure to neutralized radicals containing fluorine atoms in a plasma, as model analytes, the conductance of the SWCNT matt showed fast modulation. The transduction mechanism was investigated by electrical transport measurements, X-ray photoelectron spectroscopy and Raman spectroscopy. Metallic nanotubes were shown to react covalently to the near exclusion of semiconducting species. The selectivity was promoted by the curvature-induced strain of the nanotubes. The results open new opportunities for the detection of fluorine radicals at specific locations inside the reaction zone using a simple, miniaturized carbon nanotube network.

The development of a large-area plasma source with high density plasmas is desired for a variety of plasma processes from microelectronics fabrication to flat panel display device fabrication. In this study, a novel internal-type linear inductive antenna referred to as “double comb-type antenna” was used for a large-area plasma source with the substrate area of 880 mm × 660 mm and the effect of plasma confinement by applying multi-polar magnetic field was investigated. High density plasmas on the order of 3.2 × 1011 cm−3 which is 50% higher than that obtained for the source without the magnetic field could be obtained at the pressure of 15 mTorr Ar and at the inductive power of 5,000 W with good plasma stability. The plasma uniformity

Atmospheric pressure plasma was generated using a modified dielectric barrier discharge (pin-to-plate DBD) with the power electrode consisting of multi-pins instead of a conventional blank planar plate. The discharge and amorphous silicon (a:Si) etching characteristics of the pin-to-plate DBD were compared with those of the conventional DBD at various N2/NF3 mixtures. The pin-to-plate DBD showed higher power consumption and higher discharge current than the conventional DBD-type at a given voltage. Therefore, the pin-to-plate DBD appeared to be more efficient than the conventional DBD. In addition, the pin-to-plate DBD showed higher a:Si etch rates than the conventional DBD at various N2/NF3 mixtures. With the pin-to-plate DBD, a maximum etch rate of a:Si of 72 nm/s were obtained with an electrode size of 170 mm × 100 mm, a gas mixture of 0.75% NF3 in N2 and an AC voltage of 18 kV when the sample was stationary.

A semi-transparent cathode composed of Cs (0.5 nm)/Al (2.0 nm)/Ag (20 nm) at the wavelength of 515 nm exhibited the transmittance of 52% and the reflectance of 46%, respectively. The top-emitting device with the glass/Ag (100 nm)/tin-doped indium oxide (ITO, 125 nm)/4,4',4''-tris[2-naphthylphenyl-1-phenylamino]triphenylamine (2-TNATA, 30 nm)/4,4'-bis[N-(1-napthyl)-N-phenyl-amino]-biphenyl (NPB, 15 nm)/tris(8-quinolinolato) aluminum(III) (Alq3, 55 nm)/Cs (0.5 nm)/Al (2 nm)/Ag (20 nm)/Alq3 (52 nm) structure showed the maximum luminance of 77,200 cd/m2. Also, the external quantum efficiency and the power efficiency at about 1,000 cd/m2 were 1.9% and 2.5 lm/W, respectively. It shows about 2 times higher luminous efficiency, compared to the same device structure having lithium fluoride instead of cesium.

The energy and the flux of the ion gun with a three-grid system was compared with those of the ion gun with a two-grid system and the characteristics of the neutral beam sources composed of the ion guns with different grid systems and a reflector for the low angle reflection of the ions were investigated. By using the three-grid system instead of the two-grid system and by applying higher negative voltage to the 2nd grid, a higher ion flux without changing the ion energy could be obtained for the ion gun of the neutral beam source. The three-grid ion gun system generated higher neutral beam fluxes compared to the two-grid ion gun system. This result was confirmed by measuring the etch rates of Si and GaAs with Ar and fluorine neutral beam. Also, using the neutral beam source with the three-grid ion gun, 35nm-width Si patterns could be etched vertically by CF4 gas indicating the formation of a parallel neutral beam.

An internal linear inductive antenna referred to as “double comb-type antenna” was used for a large-area plasma source with the substrate area of 880mm × 660mm and the effects of multi-polar magnetic field applied by inserting permanent magnets parallel to the linear internal antennas on the plasma characteristics were investigated. By applying the multi-polar magnetic field, high density plasmas on the order of 3.2 × 1011-3 which is 50% higher than that obtained for the source without multi-polar magnetic field could be obtained at the RF power of 5000W. Also stable impedance matching with a low Q-factor of the plasma system could be obtained. The application of the multi-polar magnetic field not only increased the plasma density but also improved the plasma uniformity (less than 3%) within the 880mm × 660mm processing area.

An inductively coupled plasma source with internal-type linear inductive antennas named as “internal multiple U-type antenna” was developed for the substrate size of 2 300 × 2 000 mm2 and the characteristics of the large-area inductive plasma source were investigated. High density plasmas on the order of 1.18 × 1011 cm−3 could be obtained at the pressure of 15 mTorr Ar gas and the RF power of 8 kW with good plasma stability. In addition, by using variable capacitors at the end of the antenna, lower antenna voltage and more uniform antenna voltage distribution could be obtained. When a photoresist film was etched using O2 plasma with 8 kW RF power, an etch uniformity less than 11% could be obtained using the multiple U-type antenna on the substrate size larger than 7th generation (2 200 × 1 870 mm2).

In this study, the effect of BCl 3 /C 4 F 8 gas mixture on the ZrO x etch rates and the etch selectivities of ZrO x /Si were investigated and its etch mechanism was studied. The increase of C 4 F 8 in BCl 3 /C 4 F 8 decreased the silicon etch rate significantly and finally deposition instead of etching occurred by mixing C 4 F 8 more than 3%. In the case of ZrO x , the etch rate remained similar until 4% of C 4 F 8 was mixed, however, the further increase of C 4 F 8 percentage finally decreased the ZrO x etch rate and deposition instead of etching occurred by mixing more than 6%. Therefore, by mixing 3–4% of C 4 F 8 to BCl 3 , infinite etch selectivity of ZrO x /Si could be obtained while maintaining the similar ZrO x etch rate. The differences in the etch behaviors of ZrO x and Si were related to the different thickness of C–F polymer formed on the surfaces. The thickness of the C–F polymer on the ZrO x surface was smaller due to the removal of carbon incident on the surface by forming CO x with oxygen in ZrO x . Using 12 mTorr BCl 3 /C 4 F 8 (4%), 700 W of rf power, and − 80 V of dc bias voltage, the ZrO x etch rate of about 535 A/min could be obtained with infinite etch selectivity to Si.

A novel internal-type linear inductive antenna, referred to as a “double comb-type antenna”, was used as a large-area plasma source with a substrate area of 880 mm × 660 mm. This study investigated the effect of a multi-polar magnetic field on plasma confinement. High density plasma in the order of 3.2 × 10 11 cm − 3 , which is 50% higher than that obtained for a source without a magnetic field, with good plasma stability was obtained at a pressure of 15 mTorr Ar and an RF power of 5000 W. Plasma uniformity

The effects of pin-to-plate type atmospheric pressure plasma treatment on the field emission properties of screen printed carbon nanotubes(CNTs) were investigated using He(10 slm)/N2(0.1 slm). The plasma treatment for 10 s decreased the turn-on field from 3.13 V/μm to 1.21 V/μm, increased the emission current, and increased the number of emission sites. When, the 10 s plasma treatment was also applied to the CNTs which were previously treated by a tape activation method, the number of emission sites were further increased, therefore, the emission uniformity was improved even though, the plasma treatment on the tape-activated CNTs increased the turn-on field slightly 0.76 V/μm to 1.25 V/μm due to the removal of long CNTs.

In this study, two-wavelength white organic light-emitting devices (WOLEDs) were fabricated using a single doped layer, which was obtained by forming a recombination zone in a single emissive layer. In this emissive layer, both blue emission and yellow emission were obtained using a 4,4'-bis(2,2'-diphenylethen-1-yl)biphenyl (DPVBi) host doped with a red fluorescent dye, 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB). The white light resulted from the excitation in this single emissive layer by controlling the concentration of fluorescent dye in the emissive layer. In addition, a higher efficiency could be obtained using organic layers/Li/Al in the WOLED structure instead of organic layers/LiF/Al. The electroluminescent (EL) spectrum of the device was not sensitive to the driving voltage of the device. The obtained WOLEDs showed a maximum luminance of approximately 64,200 cd/m2 and the device began to emit light (at luminance of 0.1 cd/m2) at 3.4 V. At a luminance of approximately 100 cd/m2, the external quantum and the power efficiencies were 2.47% and 4.27 lm/W, respectively.

To fabricate the top-emitting organic light-emitting diodes (TEOLEDs) with an improved device performance, an n-type indium oxide (IO) was deposited as the transparent conducting capping layer, by using ion beam-assisted deposition (IBAD) technique, on the device of glass/Ag (100 nm)/ITO (100 nm)/2-TNATA (60 nm)/NPB (20 nm)/Alq 3 (40 nm)/LiF (1 nm)/Al (2 nm)/Ag (20 nm), and its properties were investigated. To minimize the damage to the organic layers and the oxidation of the top Ag layer during the oxygen IBAD, two-step processing of IO thin film composed of argon IBAD followed by oxygen IBAD was used. The light output of TEOLED fabricated by using the IBAD was similar compared with that of a reference device composed of glass/Ag (100 nm)/ITO (100 nm)/2-TNATA (60 nm)/NPB (20 nm)/Alq 3 (40 nm)/LiF (1 nm)/Al (2 nm)/Ag (20 nm)/Alq 3 (52 nm), where, Alq 3 was used as the semi-passivated capping layer.

In this study, the effects of indium tin oxide (ITO) surface treatment by various inductively coupled plasmas using O 2 , CF 4 , and CH 4 on the device characteristics of the organic light emitting diodes (OLEDs) consisted of ITO glass/2-TNATA/α-NPD/Alq 3 /LiF/Al were investigated. Among the various plasma treatments, the treatment by the CF 4 plasma showed the best OLED device characteristics while the treatment by the CH 4 plasma showed the worst OLED characteristics. The best OLED device characteristics obtained with the CF 4 plasma treatment was believed to be related to the decrease of hole injection barrier by the formation of a thin CF x buffer layer between the ITO and OLED material in the OLED device. Also, it was believed to be related to the decrease of hole injection property by the increase of work function and the decrease of resistance of ITO with the increase of the (O + F)/(In + Sn) ratio and the decrease of the Sn 4+ /In ratio on the ITO surface after the CF 4 plasma treatment. The OLED device obtained after the ITO surface treatment by the CF 4 plasma decreased the turn-on voltage from 4.8 to 3.0 V, increased the highest power efficiency from ∼ 0.58 to 1.35 lm/W, and increased the highest luminescence from 29,000 to 50,000 cd/m 2 .

Carbon nanotubes (CNTs) were grown as a function of NiCr thickness using a modified atmospheric pressure plasma containing NH3(210 sccm)/N2(100 sccm)/C2H2(150 sccm)/He(8 slm) at low substrate temperatures (≤ 500 °C), and their physical and electrical characteristics were investigated for possible applications to field emission devices. The number of defects in the grown CNTs was decreased with increasing substrate temperature and the highest CNT growth rate of 1.0 μm/min was obtained at 500 °C with 10 nm thick NiCr. The turn-on electric fields of the CNTs grown at 450 and 500 °C with 10 nm thick NiCr were 2.6 V/μm and 3.7 V/μm, respectively.

In this study, SiO x N y thin film was deposited by plasma enhanced chemical vapor deposition at the temperature lower than 40 °C using hexamethyldisilazane (HMDS)/Ar while varying the ratio of O 2 /NH 3 . And, its physical and chemical characteristics of the deposited SiO x N y as a diffusion barrier to water permeation applied to organic thin film transistors (OTFTs) were investigated. When oxygen ratio ( R ) in O 2 /NH 3 ( R = O 2 /(O 2 + NH 3 ) was lower than 0.3, due to the high remaining binding states such as –CH x and N–H in the deposited film, the deposited film was soft and easily peeled off. With increasing R , oxygen-rich, hard, and transparent SiO x N y thin film was deposited with lower –CH x and N–H. When a thin film composed of parylene (100 nm)/SiO x N y (60 nm)/parylene (100 nm) was formed on the polyethersulfone (PES, 200 μm) film with SiO x N y deposited with R = 0.5, water vapor transmission rate (WVTR) of 0.3 gm/(m 2 day) could be obtained. It is believed that, by using a multilayer SiO x N y structure, the WVTR required for OTFTs (∼ 10 − 2 gm/(m 2 day) could be obtained.

Cross-point array (CPA) structure memories using a memristor are attracting a great deal of attention due to their high density integration with a 4F2 cell. However, a common significant drawback of the CPA configuration is crosstalk between cells. To date, the CPA structure using a redox-based memristor has restrictions to minimize the operating current level due to their resistive switching mechanism. This study demonstrates suitable characteristics of a ferroelectric tunnel junction (FTJ) for the memristor of the CPA structure using an electrostatic model. From the FTJ of the Au/p-type Pr0.98Ca0.02MnO3 (4 nm)/BaTiO3 (4.3 nm)/n-type Ca0.98Pr0.02MnO3 (3 nm)/Pt(111) structure, which has a higher and thicker potential barrier, a good memristive effect for the CPA structure with a high nonlinear current-voltage curve and low current operation, was obtained by Δ Fowler-Nordheim tunneling with effectively blocked direct tunneling and thermionic emission. The FTJ demonstrated reduced sneak current and the possible for high nonlinearity.

A few-layered molybdenum disulfide (MoS2) thin film grown by plasma enhanced chemical vapor deposition was etched using a CF4 inductively coupled plasma, and the possibility of controlling the MoS2 layer thickness to a monolayer of MoS2 over a large area substrate was investigated. In addition, damage and contamination of the remaining MoS2 layer surface after etching and a possible method for film recovery was also investigated. The results from Raman spectroscopy and atomic force microscopy showed that one monolayer of MoS2 was etched by exposure to a CF4 plasma for 20 s after an initial incubation time of 20 s, i.e., the number of MoS2 layers could be controlled by exposure to the CF4 plasma for a certain processing time. However, XPS data showed that exposure to CF4 plasma induced a certain amount of damage and contamination by fluorine of the remaining MoS2 surface. After exposure to a H2S plasma for more than 10 min, the damage and fluorine contamination of the etched MoS2 surface could be effectively removed.

The effect of Ar+ ion energy on the removal of the polymethyl methacrylate (PMMA) residue remaining on the chemical vapor deposited (CVD) graphene surface without damaging the graphene surface was investigated. Stable and low energy Ar+ ion beams having a mono-energetic energy distribution with a peak energy of 7.5 eV or 11.5 eV could be formed by using a two-grid magnetically enhanced ICP ion gun with and without the application of 25 Gauss axial magnetic field, respectively, while controlling the Ar gas flow rate. When the CVD graphene treatment was performed with the Ar+ ions having the ion energy peak at 7.5 eV (with the magnetic field) and 11.5 eV (without the magnetic field), the blue shift of Raman G peak from p-type doped to intrinsic graphene indicating the removal of residue on the graphene surface could be observed for both conditions, however, the graphene treated at 11.5 eV (without the magnetic field) showed the increase of the defect while that treated at 7.5 eV (with the magnetic field) showed no significant change of the defect. It is believed that, for the treatment of CVD graphene, possibly due to the low binding energy area such as grain boundaries and domains in the CVD graphene, low energy ions with less than the energy of 10 eV is required not to damage the graphene surface, and a magnetically enhanced ICP ion gun which can provide stable and low energy Ar+ ions with a mono-energetic ion energy distribution with a peak of 7.5 eV can be applicable to the residue removal on the graphene surface.

The etch characteristics of magnetic tunneling junction (MTJ) related materials such as CoFeB, MgO, FePt, Ru, and W as hard mask have been investigated as functions of rf pulse biasing, substrate heating, and CH4/N2O gas combination in an inductively coupled plasma system. When CH4/N2O gas ratio was varied, at CH4/N2O gas ratio of 2:1, not only the highest etch rates but also the highest etch selectivity over W could be obtained. By increasing the substrate temperature, the linear increase of both the etch rates of MTJ materials and the etch selectivity over W could be obtained. The use of the rf pulse biasing improved the etch selectivity of the MTJ materials over hard mask such as W further. The surface roughness and residual thickness remaining on the etched surface of the CoFeB were also decreased by using rf pulse biasing and with the decrease of rf duty percentage. The improvement of etch characteristics by substrate heating and rf pulse biasing was possibly related to the formation of more stable and volatile etch compounds and the removal of chemically reacted compounds more easily on the etched CoFeB surface. Highly selective etching of MTJ materials over the hard mask could be obtained by using the rf pulse biasing of 30% of duty ratio and by increasing the substrate temperature to 200 degrees C in the CH4/N2O (2:1) plasmas.

The study of etching characteristics and mechanisms for HfO2 and Si in CF4/O2/Ar and CHF3/O2/Ar inductively-coupled plasmas was carried out. The etching rates of HfO2 thin films as well as the HfO2/Si etching selectivities were measured as functions of Ar content in a feed gas (0-50% Ar) at fixed fluorocarbon gas content (50%), gas pressure (6 mTorr), input power (700 W), bias power (200 W), and total gas flow rate (40 sccm). Plasma parameters as well as the differences in plasma chemistries for CF4- and CHF3-based plasmas were analyzed using Langmuir probe diagnostics and 0-dimensional plasma modeling. It was found that, in both gas systems, the non-monotonic (with a maximum at about 15-20% Ar) HfO2 etching rate does not correlate with monotonic changes of F atom flux and ion energy flux. It was proposed that, under the given set of experimental conditions, the HfO2 etching process is affected by the factors determining the formation and decomposition kinetics of the fluorocarbon polymer layer. These factor are the fluxes of CF(x) (x = 1, 2) radicals, O atoms and H atoms.

Etching characteristics and mechanisms of low-temperature SiN(x) thin films for nano-devices in CH2F2/O2/Ar inductively-coupled plasmas were studied. The etching rates of SiN(x) thin films as well as the etching selectivities over Si and photoresist were measured in the range of 25-75% O2 in a feed gas at fixed CH2F2 content (25%), gas pressure (6 mTorr), input power (900 W), bias power (200 W), and total gas flow rate (40 sccm). Plasma parameters were analyzed using the Langmuir probe diagnostics and optical emission spectroscopy. The chemical states of the etched surfaces were examined by the X-ray photoelectron spectroscopy. It was found that the non-monotonic (with a maximum at about 50-60% O2) SiN(x) etching rate does not correlate with monotonically decreasing F atom flux and ion energy flux. It was proposed that, under the given set of experimental conditions, the SiN(x) etching process is also controlled by the O and H atom fluxes through the destruction of the fluorocarbon polymer layer.

RF pulsed plasma characteristics of inductively coupled plasma (ICP) sources operated with internal linear type antennas for the next generation display processing were investigated. By applying the rf pulse mode in the ICP source, with decreasing the rf pulse duty percentage, the average electron temperature was decreased and the plasma non-uniformity was improved with decreasing the rf pulse duty percentage. In the case of plasma uniformity, for the same time average rf power of 3 kW to the ICP source, the plasma non-uniformity was improved from 8.4% at 100% of rf duty percentage to 6.4% at 60% of rf duty percentage due to the increased diffusion of the plasma during the pulse-off time. When SiO2 was etched using CF4, the etch rate uniformity was also improved due to the improvement of plasma uniformity.

The magnetic tunnel junction (MTJ)-related materials such as CoFeB, CoPt, MgO, and Ru, and W were etched using CH3OH in a pulse-biased inductively coupled plasma system and the effect of bias pulsing (100% 30% duty percentage) on the etch characteristics of the MTJ-related materials was investigated at the substrate temperature of 200 degrees C. The etch selectivity of MTJ-related materials over W was improved by using pulse-biasing possibly due to the formation of more stable and volatile etch products during the pulse-off time and the removal of the compounds more easily on the etched CoFeB surface during the pulse-on time. X-ray photoelectron spectroscopy also showed that the use of lower duty percentage decreases the residue thickness remaining on the etched MTJ materials indirectly indicated the higher volatility of the etch products by the bias pulsing. The etching of nano-patterned CoFeB masked with W also showed more anisotropic etch profile by pulse-biasing probably due to the increased the etch selectivity of CoFeB over W and the decreased redeposition of etch products on the sidewall of the CoFeB features. The most anisotropic CoFeB etch profiles could be observed by using CH3OH gas in the pulse biasing of 30% duty ratio.

By plasma-enhanced chemical vapor deposition, a molybdenum disulfide (MoS2 ) thin film is synthesized directly on a wafer-scale plastic substrate at below 300 °C. The carrier mobility of the films is 3.74 cm(2) V(-1) s(-1) . Also, humidity is successfully detected with MoS2 -based sensors fabricated on the flexible substrate, which reveals its potential for flexible sensing devices.

SiO x N y thin films were deposited by inductively coupled plasma enhanced chemical vapor deposition (ICP-PECVD) using hexamethyldisilazane (HMDS, 99.9%)/NH 3 /O 2 /Ar at a low temperature, and examined for use as a water vapor diffusion barrier. The film characteristics were investigated as a function of the O 2 :NH 3 ratio. An increase in the O 2 :NH 3 ratio decreased the level of impurities such as –CH x , N–H in the film through a reaction with oxygen. Thereby, a more transparent and harder film was obtained. In addition, an increase in the O 2 :NH 3 ratio decreased the nitrogen content in the film resulting in a more SiO 2 -like SiO x N y film. Using SiO x N y fabricated with an O 2 :NH 3 ratio of 1:1, a multilayer thin film consisting of multiple layers of SiO x N y /parylene layers was formed on a polyethersulfone (PES, 200 μm) substrate, and its water vapor transmittance rate (WVTR) was investigated. A WVTR 2 day) applicable to organic thin film transistors or organic light emitting diodes was obtained using a multilayer composed of SiO x N y (260 nm)/parylene (

Three-wavelength white organic light-emitting diodes (WOLEDs) were fabricated using two doped layers, which were obtained by separating the recombination zones into three emitter layers. A sky blue emission originated from the 4,4′-bis(2,2′-diphenylethen-1-yl)biphenyl (DPVBi) layer. A green emission originated from a tris(8-quinolinolato)aluminum (III) (Alq 3 ) host doped with a green fluorescent 10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano [6,7,8-ij]-quinolizin-11-one (C545T) dye. An orange emission was obtained from the N , N ′-bis(1-naphthyl)- N , N ′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) host doped with a red fluorescent dye, 4-(dicyanomethylene)-2- tert -butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB). A white light resulted from the partial excitations of these three emitter layers by controlling the layer thickness and concentration of the fluorescent dyes in each emissive layer simultaneously. The electroluminescent spectrum of the device was not sensitive to the driving voltage of the device. The white light device showed a maximum luminance of approximately 53,000 cd/m 2 . The external quantum and power efficiency at a luminance of approximately 100 cd/m 2 were 2.62% and 3.04 lm/W, respectively.

A new five-coordinated bis(2,4-dimethyl-8-quinolinolato)(triphenylsilanolato)aluminum (III) (24MeSAlq) material, having bulky substituents, was prepared in one-step reaction and was characterized. The photoluminescent (PL) spectrum of 24MeSAlq shows the largest hypsochromic shift exhibiting the maximum wavelength at the peak of 461 nm among the blue-emitting q 2 AlOR-type complexes (q = 8-quinolinolato ligand and OR = aryloxy or alkoxy ligand) reported. The deep blue device composed of ITO/2-TNATA (60 nm)/NPB (15 nm)/24MeSAlq (20 nm)/Alq 3 (45 nm)/LiF (1 nm)/Al (100 nm), which uses 24MeSAlq as a hole-blocking layer and applies a principle efficiently confining an exciton recombination zone into a hole transporting layer, shows the maximum electroluminescent (EL) at the peak of 446 nm originating from the NPB emissive layer. This is attributed to an excellent hole-blocking property due to the high HOMO (highest occupied molecular orbital) energy level (6.14 eV).

In this study, the growth behavior of carbon nanotubes(CNT) deposited from C 2 H 2 by an atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD) method was investigated. The deposition was performed at 400 °C using a modified dielectric barrier discharge using He/C 2 H 2 with additive gases such as N 2 and NH 3 . The effect of the pretreatment on the surface morphology of the Ni catalyst was also investigated. Treatment of the Ni catalyst surface with a He (6 slm)/NH 3 (90 sccm) atmospheric pressure plasma for 5 min at 400 °C transformed the Ni surface into more uniformly agglomerated small Ni particles required for the enhanced carbon diffusion during the CNT formation. The CNTs grown by using He (6 slm)/C 2 H 2 (90 sccm) AP-PECVD with additive gases (NH 3 , N 2 ) for 5 min at 400 °C after the pretreatment showed uniform 1.5–2 μm long and 20–50 nm diameter multi-layer CNTs. By the application of − 1.2 kV of dc bias to the substrate during the growth CNTs by the AP-PECVD, more vertical CNTs could be obtained. FT-Raman data showed the grown CNTs are muti-wall CNTs and have the intensity ratio of D-band/G-band was 0.8–0.9, so defects were involved in the grown CNTs. This study provides a new method growing CNTs at atmospheric pressure and at low temperature, which has special advantages for large scale applications using conventional glass substrates.

In this study, two different types of internal linear antennas were compared and their characteristics were investigated for a large area ICPs applied to FPD processing. The measured plasma density for the double comb-type antenna was higher than 2 × 1011/cm3 and the etch rates of photoresist and SiO2 at 5000 W rf power, − 60 V of dc-bias voltage, and 15 mTorr SF6 were about 3000 A/min and 1500 A/min. The etch non-uniformity of the photoresist within the substrate was about 7% at 5000 W of rf power.