Search

Abstract The solvent vapor annealing (SVA) technique is one of the useful post processing techniques of a thin film, which is an alternative technique of the thermal annealing one. SVA has a great advantage that the molecular rearrangement in the film is made moderately by employing an appropriate solvent without the sample heating. The moderate processing is expected to yield a benefit that the molecular coalescence would be suppressed, which would readily keep the continuous surface topography of the film during the annealing, and another benefit that a metastable structure would be obtained. To make the best use of the SVA-specific characteristics, in the present study, a material having a metastable structure is chosen. The sample is zinc tetraphenylporphyrin (ZnTPP) that yields a metastable triclinic crystal structure, which can easily be converted to a monoclinic crystal structure by thermal annealing. A triclinic-structure film of ZnTPP by the combination of a wet process and the thermal annealing has thus never been reported. By choosing a fluorine-containing solvent, which has a low affinity to ZnTPP, a triclinic-structure film has first been obtained by a wet process while the surface continuity is protected. Highlights • A metastable triclinic crystal of ZnTPP is first obtained by a wet process. • A weak affinity solvent to ZnTPP makes the solvent vapor annealing successful. • The continuous surface topography of the ZnTPP film is readily remained. • The characterization is performed by using the 2D-GIXD and IR pMAIRS techniques. [ABSTRACT FROM AUTHOR]

The work reports plasma assisted growth of nitrogen-doped titanium dioxide (N-TiO 2 ) thin films using high power impulse magnetron sputtering (HiPIMS) power source and effect of post-deposition thermal annealing. The films were deposited at low pressure. The binding energies of elements of interest, the energy gap, crystallinity and morphology of the films were analyzed before and after annealing. The results showed an increase in binding energies, a fact attributed to enhanced oxidation, after the annealing process. Only nitrogen doped samples grown by HiPIMS exhibited the presence of substitutional nitrogen. The energy gap of the films was found to decrease after doping and annealing. Improvement in crystallinity with a small shift in the crystalline peaks indicating decrease in lattice parameter, which could be seen by surface smoothing, was observed after thermal annealing. As a result of the growth of films by HiPIMS, nitrogen doping and post-deposition thermal annealing, improvements in the properties of the films which have relevance for photocatalytic and energy applications were observed. [ABSTRACT FROM AUTHOR]

The influences of sulfurization process on Cu 2 ZnSnS 4 (CZTS) film characters were investigated through soft-annealing and sulfurization precursors, which were prepared by sputtering at room temperature with metal targets and sulfide targets. The Sn-loss of CZTS film was researched by comparing different CZTS films based on metallic precursors and sulfur-contained precursors. As a result, the CZTS film based on metallic precursors showed more serious Sn-loss than that from sulfur-contained precursors. Moreover, the experimental results also demonstrated that an appropriate temperature-time profile during sulfuring process can act as a crucial factor on the morphologies and Sn-loss of CZTS films, and the CZTS films with fine morphologies and appropriate composition were obtained by modifying the time-temperature profile during sulfurization process. Finally, the best solar cell with efficiency of 2.81% was obtained based on the metallic precursor. [ABSTRACT FROM AUTHOR]

We synthesized CuIn 0.7 Ga 0.3 Se 2 thin films on soda lime glass substrates using pulsed laser deposition and post-annealing under different conditions. Increasing substrate temperature during deposition and vacuum annealing after deposition both increased grain size but had negligible effect on the electronic properties of the films. As-deposited films demonstrated P-type conductivities with high carrier concentrations and low Hall mobilities, but annealing in elemental sulfur environment significantly improved the electronic properties of the films. We found that the incorporation of even small quantities of sulfur into the films reduced carrier concentrations by over three orders of magnitude and increased Hall mobilities by an order of magnitude. This resulted in films with resistivity ~ 5 Ω·cm suitable for photovoltaic applications. [ABSTRACT FROM AUTHOR]

In the following article the influence of selenium supply on the stacked elemental layer process during the final annealing step is investigated. We find that the Se supply strongly influences the phase formation in the Cu(In,Ga)Se 2 resulting in a modified Ga/In distribution. The effects of Se supply on the structural and electronic properties of the films are reported. The solar cell performance has been investigated in detail using current voltage and external quantum efficiency measurements. We find that the chalcopyrite crystal formation is strongly influenced by the Se supply during the growth process. Furthermore the interdiffusion of Ga and In is accelerated with increasing Se amount. This has direct consequences on band gap and series resistance, which leads to changes in the values of short-circuit current density, open-circuit voltage and fill factor. The open-circuit voltage increases with increasing band gap of the Cu(In,Ga)Se 2 , whereas the short-circuit current density decreases with increasing band gap. The fill factor is affected by the formation of MoSe 2 at the back contact. The experimental findings are compared with the theoretical efficiency limits calculated from the Shockley–Queisser model, and also with numerical 1D SCAPS simulations. [ABSTRACT FROM AUTHOR]

Cu 2 ZnSnS 4 (CZTS) is a promising material for thin film solar cell applications because of its excellent photovoltaic properties, high abundance and non-toxicity. Thin films of CZTS are generally fabricated by vacuum based techniques or by using toxic solvents and these routes reduce its attention as a low cost and environmental friendly material. In this study, we have prepared CZTS through a solution based single step approach using non-toxic chemicals by spin coating and studied the effect of annealing temperature in the range 350–550 °C in nitrogen atmosphere on structural, optical and electrical properties. XRD results revealed the formation of kesterite phase at all annealing temperatures, while the Raman studies indicated Cu 2 SnS 2 impurity phase in the film annealed at 550 °C. Band gap of the films annealed in nitrogen varies from 1.46 eV to 1.56 eV, depending on the annealing temperature. Optimum properties, such as, good crystallinity, dense structure, ideal band gap (1.49 eV) and good absorption coefficient (10 4 cm − 1 ), were obtained for the film annealed at 500 °C for 30 min in nitrogen. [ABSTRACT FROM AUTHOR]

The mechanical behavior of Microelectromechanical systems (MEMS) devices is significantly influenced by fabrication processes conditions, deposition steps and geometry, e.g., processing temperature, thickness of thin film layers, deposition rate, etc. These processes under different deposition temperature will generate residual stress/strain in thin film layers, which will affect device sensing stability, accuracy and robustness, therefore, predicting and minimizing the residual stress become a critical issue on thin film devices design. This research develops a simulation methodology using finite element analysis (FEA) with process modeling technology to analyze the thermal stress/strain of thin films varying on different process procedures in a selected MEMS microphone device. In general, the residual stress/strain of multi-layers thin film is combined of intrinsic and thermal stresses, the thermal induced mechanical stress can be obtained using FEA but intrinsic stress which contains many uncertainties is very difficult to be defined. The residual stress in thin film layer on each processing procedure can be obtained from Stoney's equation. A comparison of the experiment and simulation results showed that the combined thermal induced stress and dislocation induced intrinsic stress in aluminum thin film will be rearranged after first annealing. The intrinsic stress, however, will affect the final residual stress when thickness of aluminum film is under 1 μm. The residual stress and the warpage of MEMS microphone are predicted by using processing modeling technology. The polysilicon will warp downward if the diaphragm is subjected to compressive stress. However, the polysilicon film will have much less warpage when intrinsic stress is positive. [ABSTRACT FROM AUTHOR]

Compound evaporated indium sulfide is one commonly utilized cadmium free buffer layer for Cu(In,Ga)(S,Se) 2 solar cells. However, cells with such a buffer layer usually need a post-deposition annealing step to reach the maximum short circuit current, fill factor and open circuit voltage. In this work wet chemical treatments, partly containing cadmium ions, are applied to commercially available absorber material prior to indium sulfide evaporation in order to enhance the initial solar cell parameters. Cells built on treated absorbers show maximum open circuit voltage directly after window layer deposition and a drop in open circuit voltage is observed upon annealing. All samples, however, show an increased collection length and higher fill factor after annealing. A one diode model fit to the current–voltage curves gives ideality factors of 1.7 before annealing which are reduced to values around 1.5 after annealing. Supporting calculations show that the changes upon annealing can be explained within a model including a highly p-doped absorber surface layer. During annealing the acceptor density at the absorber surface might be reduced thus leading to a larger space charge region and thereby increasing the collection length and fill factor while reducing the open circuit voltage. [ABSTRACT FROM AUTHOR]

Abstract: The quaternary semiconductor Cu2ZnSnS4 (CZTS) is a possible In-free replacement for Cu(In,Ga)Se2. Here we present reactive sputtering with the possibility to obtain homogeneous CZTS-precursors with tunable composition and a stoichiometric quantity of sulfur. The precursors can be rapidly annealed to create large grained films to be used in solar cells. The reactive sputtering process is flexible, and morphology, stress and metal and sulfur contents were varied by changing the H2S/Ar-flow ratio, pressure and substrate temperature. A process curve for the reactive sputtering from CuSn and Zn targets is presented. The Zn-target is shown to switch to compound mode earlier and faster compared to the CuSn-target. The precursors containing a stoichiometric amount of sulfur exhibit columnar grains, have a crystal structure best matching ZnS and give a broad peak, best matching CZTS, in Raman scattering. In comparing process gas flows it is shown that the sulfur content is strongly dependent on the H2S partial pressure but the total pressures compared in this study have little effect on the precursor properties. Increasing the substrate temperature changes the film composition due to the high vapor pressures of Zn, SnS and S. High substrate temperatures also give slightly denser and increasingly oriented films. The precursors are under compressive stress, which is reduced with higher deposition temperatures. [Copyright &y& Elsevier]

Abstract: Niobium was deposited as an electrode material on an n-type SiC wafer for power device application. The reaction microstructure and electrical contact property were investigated after annealing at 700 to 1000°C and compared with the results for an Ni electrode. Microstructure-related problems of the Ni electrode could be resolved without sacrificing ohmic contact behavior with a low contact resistivity of 1.53×10−4 Ωcm2. Carbon precipitation was completely eliminated with Nb by the formation of carbides, leading to good adhesion upon wire bonding process. At the reaction interface, Nb5Si3 was formed in an epitaxial relationship with SiC, leading to a good interface contact property as well as good interface adhesion. [Copyright &y& Elsevier]

Abstract: Zinc sulfide (ZnS) semiconductor nanocrystal films have been prepared on indium tin oxide coated glass substrates by sulfosalicylic acid (C7H6O6S)-assisted galvanostatic deposition with subsequent annealing. The deposition was performed at 10mAcm−2 in acidic electrolytes containing 15–30mM Zn(CH3COO)2, 20mM Na2S2O3, 200mM LiCl, 0.375mM Na2SO3, and 0 or 0.2mM C7H6O6S. Results show that the presence of C7H6O6S can suppress the precipitation of Zn and S impurity phases during the ZnS deposition process. As the [C7H6O6S]=0.2mM and [Zn2+]=20mM, the deposited ZnS film exhibits only hexagonal structure with an ideal Zn/S atomic ratio of 1.03 and a close-packed granular morphology. But its band gap about 2.86eV is narrower than the common value of ZnS, probably due to the existence of some spurious acetate species and defect states. By annealing the film at 400°C for 60min, its band gap increased up to 3.70eV, despite that its crystalline phase transformed into cubic structure which usually shows the narrower band gap than hexagonal ZnS. The significant band gap widening could be ascribed to the degradation of spurious acetate species and the reduction of various possible defect states in the annealing process. [Copyright &y& Elsevier]

Abstract: Preparation and characterization of CdSe thin film semiconductors, prepared by cathodic electrodeposition from an acid sulphate solution (CdSO4–SeO2) before and after thermal treatment in nitrogen atmosphere, were investigated. The effect of the bath temperature and how it affects the cadmium selenide (CdSe) deposits were studied. The formation of compact barrier layers of zinc blende CdSe was attained. Scanning electron microscopy and X-ray diffraction patterns present a remarkably intense cubic structure, even after thermal treatment. The Ni/CdSe/Au structure may exhibit rectifying properties depending on the temperature during the electrodeposition. Thermal annealing in nitrogen gas increases the conductivity of CdSe and intensifies the rectification properties of the Ni/CdSe/Au structure. [Copyright &y& Elsevier]

Abstract: The possibility to form secondary phases during annealing of a two-phase ternary nitride material is studied. By the use of an initial multilayer structure the new phase forms at the sublayer interfaces, resulting in an enhanced layering of the film. This is illustrated by a ZrAlN/TiN thin film where formation of a cubic structure ZrTi(Al)N phase at the sublayer interfaces improves the mechanical properties after annealing above 900°C. [Copyright &y& Elsevier]

Abstract: In this paper, we reported on an approach to prepare tin disulfide (SnS2) thin films on soda-lime glass substrates by vacuum thermal evaporation using SnS2 powders as a source. The influence of annealing on the chemical composition, crystal structure, surface morphology, and optical band gap of the SnS2 thin films was systemically investigated. The as-grown SnS2 thin film was amorphous, homogeneous, smooth, nearly stoichiometric, with no pinhole and crack free, and with an optical band gap of 2.41eV. After the SnS2 thin film was annealed at 300°C, the crystallization of SnS2 was demonstrated by X-ray diffraction and scanning electron microscope with a characteristic of a preferred orientation along (001) plane with hexagonal phase and the sheet appearance of the SnS2 crystals. At the annealing temperature of 350°C, some SnS2 crystallites and a few pinholes appeared on the surface of the SnS2 thin films, though the SnS2 thin film was not oxidized. When the annealing temperature was increased to 400°C, SnS2 was gradually oxidized into an approximate spherical shape of SnO2 from the top to the bottom of the SnS2 thin film by trace O2 in the furnace. Therefore, our experiment suggested that the annealing temperature of the SnS2 thin film using the vacuum thermal evaporation should not be over 300°C as a window layer in compound thin film solar cells. [Copyright &y& Elsevier]

Abstract: Thin films of amorphous indium tin oxide were deposited by soft sputtering. The film was gradually annealed in air at temperatures from 110°C to 150°C. Its structural and electrical properties were monitored in order to get a better understanding of the annealing process. Firstly, carrier density decreases by oxygen intake. Crystallization speeds up at 150°C, with a 2.5 D growth of crystallites. The preferred orientations come from sputtering induced seeds. Then, the carrier density increases again due to tin activation. Meanwhile, the carrier mobility is more damaged by the low temperature annealing in air than by a standard annealing in a reducing atmosphere. Thus, tin oxide segregation is suspected at grain boundaries. [Copyright &y& Elsevier]

Abstract: Nitrogen-doped germanium telluride (N-GeTe) films with and without silicon nitride (SiN) layer were thermally annealed in an air atmosphere. The SiN layer prevented the oxidation of GeTe films despite the massive in-diffusion of oxygen atoms. The phase transition from cubic to rhombohedral phase occurred only in the air-annealed samples, not in the samples annealed at 2.0mPa. The in-diffused oxygen is probably the leading cause of this phase transition. N-GeTe films without SiN layer showed an increase in sheet resistance after 1000min of air annealing; this could be attributable to a phase transition from the cubic GeTe phase to the amorphous germanium oxide and metallic tellurium phases. [Copyright &y& Elsevier]

Abstract: Effects of low-temperature annealing were examined for amorphous In–Ga–Zn–O (a-IGZO) thin-film transistors (TFTs). In a previous study, we reported that O2 annealing is effective to improve performances of a-IGZO TFTs when annealed at ≥300°C, but causes large negative threshold voltage shift when annealed at ≤ 200°C. Here, we examined effects of ozone (O3) annealing on physical properties and TFT characteristics of a-IGZO in comparison with conventional O2 annealing. We found little differences in chemical composition, band gap and photoemission spectra between the O2 and the O3 annealed films. On the other hand, free electron density was suppressed well by the O3 annealing even at low temperatures ≤200°C. Moreover, even at 150°C, the TFTs characteristics were improved to the subthreshold voltage swing of 217mV/decade, the saturation mobility of ~11.4cm2(Vs)−1 and the threshold voltage of 0.1V by the O3 annealing. It was also found that the effects of the O3 annealing is more effective for thicker channel TFTs, which would be due to stronger oxidation power and the larger diffusion constant of oxygen atoms produced from O3 molecules than those of O2. These results substantiate that the O3 annealing is more effective to improve TFT characteristics in particular for low-temperature processes at ≤200°C. [Copyright &y& Elsevier]

Abstract: The stability of amorphous In–Ga–Zn–O (a-IGZO) thin-film transistors (TFTs) was investigated focusing on the effects of passivation layer materials (Y2O3, Al2O3, HfO2, and SiO2) and thermal annealing. Positive bias constant current stress (CCS), negative bias stress without light illumination (NBS), and negative bias light illumination stress (NBLS) were examined. It was found that Y2O3 was the best passivation layer material in this study in terms of all the stability tests if the channel was annealed prior to the passivation formation (post-deposition annealing) and the passivation layer was annealed at ≥250°C (post-fabrication annealing). Post-fabrication thermal annealing of the Y2O3 passivation layer produced very stable TFTs against the CCS and NBS stresses and eliminated subgap photoresponse up to the photon energy of 2.9eV. Even for NBLS with 2.7eV photons, the threshold voltage shift is suppressed well to −4.4V after 3h of test. These results provide the following information; (i) passivation removes the surface deep subgap defects in a-IGZO and eliminates the subgap photoresponse, but (ii) the bulk defects in a-IGZO should be removed prior to the passivation process. The Y2O3-passivated TFT is not only stable for these stress conditions, but is also compatible with high-frequency operation with the current gain cut-off frequency of 91kHz, which is consistent with the static characteristics. [Copyright &y& Elsevier]

Abstract: The effect of low-temperature (200°C) annealing on the threshold voltage, carrier density, and interface defect density of amorphous indium zinc oxide (a-IZO) thin film transistors (TFTs) is reported. Transmission electron microscopy and x-ray diffraction analysis show that the amorphous structure is retained after 1h at 200°C. The TFTs fabricated from as-deposited IZO operate in the depletion mode with on–off ratio of >106, sub-threshold slope (S) of ~1.5V/decade, field effect mobility (μFE) of 18±1.6cm2/Vs, and threshold voltage (V Th) of −3±0.7V. Low-temperature annealing at 200°C in air improves the on-current, decreases the sub-threshold slope (1.56 vs. 1.18V/decade), and increases the field effect mobility (μFE) from 18.2 to 23.3cm2/Vs but also results in a V Th shift of −15±1.1V. The carrier density in the channel of the as-deposited (4.3×1016 /cm3) and annealed at 200°C (8.1×1017 /cm3) devices were estimated from test-TFT structures using the transmission line measurement methods to find channel resistivity at zero gate voltage and the TFT structures to estimate carrier mobility. [Copyright &y& Elsevier]

Abstract: High-k Tb2O3 films deposited on strained-Si:C and treated with different post-rapid thermal annealing temperatures were formed as alternative gate dielectrics in metal oxide semiconductor devices. The dielectrics were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, atomic force microscopy, and electrical measurements. It was found that Tb2O3 dielectrics properly annealed at 800°C form well-crystallized Tb2O3 structures with few defects. [Copyright &y& Elsevier]

Abstract: Current density-voltage characteristics of Si p+-i-n+ interband tunneling diodes are presented. The diodes were fabricated by low-temperature molecular beam epitaxy. Very high and abrupt p- and n-type dopant transitions into the 1020 cm−3 ranges are achieved by boron and antimony, respectively. The Esaki structures are realized without a post growth annealing step. The silicon Esaki diodes show negative differential resistance with excellent peak to valley current ratios up to 5.3. An increase of the width of the tunneling barrier results in a dramatic decrease of the peak current density. 10nm additional Si changes the current over more than 6 decades. [Copyright &y& Elsevier]

Abstract: In silicon crystals annealed at 1173K, n-type dopant atoms segregate nearby a stacking fault ribbon bound by a pair of partial dislocations and the width of the ribbon is increased. The origin of the width increase is the reduction of the stacking fault energy due to an electronic interaction between the ribbon and the dopant atoms segregating at the ribbon, rather than the reduction of the strain energy around the partial dislocations due to the dopant atoms segregating at the partials. [Copyright &y& Elsevier]

Abstract: We proposed the low temperature formation technique of strain-relaxed Si1−x−yGexSny-on-insulator (SGTOI) structures. We found that the solid-phase reaction and the formation of single and uniform Si1−x−yGexSny layer on an insulator after annealing SiO2/Ge1−zSnz/SOI structures even at a temperature as low as 400°C. We characterized the crystalline structure of SGTOI, and investigated the effects of annealing, Sn incorporation, and a SiO2 cap layer on the solid-phase reaction between Ge1−zSnz and SOI layers. The solid-phase reaction is enhanced with a higher Sn content and a thicker SiO2 cap layer, and then Si1−x−yGexSny layers are more rapidly formed. The SGTOI layer exhibits very low mosaicity and have good crystallinity. [Copyright &y& Elsevier]

Abstract: The solid phase epitaxy (SPE) of undoped amorphous Si (a-Si) deposited on SiO2 patterned Si(001) wafers by reduced pressure chemical vapor deposition (RPCVD) using a H2–Si2H6 gas system was investigated. The SPE was performed by applying in-situ postannealing directly after deposition process. By transmission electron microscopy (TEM) and scanning electron microscopy, we studied the lateral SPE (L-SPE) length on sidewall and mask for various postannealing times, temperatures and a-Si thicknesses. We observed an increase in L-SPE growth for longer postannealing times, temperatures and larger Si thicknesses on mask. TEM defect studies revealed that by SPE crystallized epi-Si exhibits a higher defect density on the mask than at the inside of the mask window. By introducing SiO2-cap on the sample with 180nm Si thickness following postannealing at 570°C for 5 h, the crystallization of up to 450nm epi-Si from a-Si is achieved. We demonstrated the possibility to use this technique for SiGe:C heterojunction bipolar transistor (HBT) base layer stack to crystallize Si-buffer layer to widen the monocrystalline region around the bipolar window and to improve base link resistivity of the HBT. [Copyright &y& Elsevier]

Abstract: Both direct and indirect band gap transitions are observed in Ge by photoluminescence and electroluminescence. The relative emission intensity of direct band gap transition with respect to indirect band gap transition increases with the increase of the n type doping level, optical pumping power, injection current density, temperature, and strain. The enhancement of direct band gap transition is due to the increase of electron population in the direct valley by reducing the difference between direct and indirect band gaps. The reduction of direct and indirect band gaps can be extracted from the emission spectra with direct and indirect transition models. The defects and the thickness dependent reabsorption are responsible for the relatively strong direct band gap transition in the Ge-on-Si sample as compared to bulk Ge. [Copyright &y& Elsevier]

Abstract: The structural properties of straight screw dislocations extended in the [001] direction formed in squared- and line shaped- Ge(001) films selectively grown on submicron regions of Si(001) substrates were investigated by transmission electron microscopy. The screw dislocations propagating as a result of spiral surface growth were redirected toward the SiO2 sidewalls. This redirection is linked to the formation of facets such as {111} facets in the growing Ge films. In the process of strain relaxation upon annealing, the screw dislocations were dissociated into dislocations with Burgers vectors of the a/2<110> type, which glided on the {111} surfaces and disappeared. [Copyright &y& Elsevier]

Abstract: We investigated the crystalline structures of Ge1−xSnx heteroepitaxial layers with Sn contents greater than 20% grown on InP and Ge substrates. Considering the lattice mismatch between the Ge1−xSnx layers and the substrates, we achieved epitaxial growth of Ge1−xSnx layers with very high Sn content by suppressing the Sn precipitation; in addition, we improved upon the crystalline quality of Ge1−xSnx heteroepitaxial layers. As a result, we could successfully form a 130nm-thick Ge1−xSnx heteroepitaxial layer on an InP substrate with a Sn content as high as 27% without Sn precipitation. We also improved the crystalline quality of Ge1−xSnx layers by annealing at a temperature as low as 290°C. [Copyright &y& Elsevier]

Abstract: Blanket and selective Ge growth on Si is investigated using reduced pressure chemical vapor deposition. To reduce the threading dislocation density (TDD) at low thickness, Ge deposition with cyclic annealing followed by HCl etching is performed. In the case of blanket Ge deposition, a TDD of 1.3×106 cm−2 is obtained, when the Ge layer is etched back from 4.5μm thickness to 1.8μm. The TDD is not increased relative to the situation before etching. The root mean square of roughness of the 1.8μm thick Ge is about 0.46nm, which is of the same level as before HCl etching. Further etching shows increased surface roughness caused by non-uniform strain distribution near the interface due to misfit dislocations and threading dislocations. The TDD also becomes higher because the etchfront of Ge reaches areas with high dislocation density near the interface. In the case of selective Ge growth, a slightly lower TDD is observed in smaller windows caused by a weak pattern size dependence on Ge thickness. A significant decrease of TDD of selectively grown Ge is also observed by increasing the Ge thickness. An about 10 times lower TDD at the same Ge thickness is demonstrated by applying a combination of deposition and etching processes during selective Ge growth. [Copyright &y& Elsevier]

Abstract: We present an effective epitaxy process based on a cyclical deposition-etch (CDE) technique to obtain ultra-low resistivity in situ phosphorus-doped silicon carbon (SiCP) layers for raised source/drain applications. The combined low process temperature and high growth rate of the CDE technique is shown to maximize the incorporation of phosphorus and carbon into the crystal. We also present a complementary procedure based upon high-temperature annealing to further improve the phosphorus activation. This process and procedure enable the formation of raised SiCP source/drains on advanced 20nm fully-depleted-silicon-on-insulator devices with a carrier density up to 3×1020 cm−3 for 5×1020 cm−3 total P, and with fully-substitutional carbon in the range from 0% to 2%. It was found that a 1250°C millisecond laser anneal improves resistivity by 30% and 42% for SiP and SiC2.1%P, respectively. This result is in contrast with a 1060°C spike anneal, where the gain in activated P is shown to be insignificant for SiCP. It is shown that the formation of C clusters or precipitates during spike anneal adversely affects P activation. With an optimized annealing process, resistivity values as low as 0.46MΩcm for SiC2.1%P and 0.3MΩcm for SiP were obtained. [Copyright &y& Elsevier]

Abstract: The 1.35-eV-bandgap energy-CuO film with the optical absorption coefficient of 2.2×104 cm−1 has been prepared on a conductive glass substrate by anodic electrodeposition in an aqueous solution containing copper (II) nitrate and ammonium nitrate at 298K followed by annealing at 573K and above in air. The as-deposited CuO film with a monoclinic lattice showed p-type conduction with resistivity of 2.2×105 Ωcm and slightly expanded bandgap energy of 1.46eV with the absorption coefficient of 1.3×104 cm−1. The annealing induced changes in the grain morphology, bandgap energy, absorption coefficient, and resistivity, and the resistivity of 3.3Ωcm could be obtained by annealing at 773K. [Copyright &y& Elsevier]

High-resolution electron microscopy at the atomic scale has been applied to study the edge dislocation redistribution between interfaces in Ge/Ge 0.5 Si 0.5 /Si(001) heterostructures. It is demonstrated that such heterostructures relax in two stages: a network of edge dislocations is formed on the Ge/GeSi interface during heterostructure growth; after that, during additional annealing, some of these edge dislocations move through the volume of initially elastically strained GeSi to the GeSi/Si interface. Our results provide a direct explanation that plastic relaxation of the GeSi buffer layer proceeds owing to motion of Lomer-type dislocation complexes consisting of a pair of complementary 60° dislocations with the ends of the {111} extra planes being located at a distance of ~ 2-12 interplanar spacings from each other. [ABSTRACT FROM AUTHOR]

• High-quality metal oxide thin film fabrication was realized by lightwave annealing at ~230 °C. • Mechanism of lightwave annealing process on solution-processed IGZO thin films was investigated. • The optimal IGZO TFTs exhibit high carrier mobility of 13.4 cm2/Vs and high I on/off of > 105. In this paper, a lightwave-derived low-temperature annealing method is demonstrated on solution-processed InGaZnO (IGZO) films for the flexible thin film transistors (TFTs) applications. It is demonstrated that lightwave-derived low-temperature annealing (~230 °C) enhances the IGZO TFTs performance. Compared with the conventional furnace annealing process, lightwave annealing can effectively facilitate the decomposition of the IGZO precursors and form a smooth and dense IGZO film. With AlO x used as a dielectric layer, the optimal IGZO TFTs exhibit the carrier mobility of 13.4 cm2/Vs and a high on-current to off-current ratio (I on /I off) of > 105. This work indicates that lightwave annealing is a practical approach to fabricate the oxide semiconductors at a low annealing temperature and show great potential for the next-generation low-cost wearable device fabrication. [ABSTRACT FROM AUTHOR]

Abstract: Reduction in the accumulation capacitance value was more in Si metal-oxide-semiconductor devices than that of Ge metal-oxide-semiconductor devices after a thermal treatment irrespective of the annealing environment. Relatively, thermal treatment in oxygen environment improves the interface quality of HfO2/Ge stacks considerably, when compared with HfO2/Si stacks. Whereas, the forming gas annealing at a temperature of 400°C was not so effective in improving the interface quality at HfO2/Si stack. The presence of induced negatively charged hydrogen atom in Ge lessens the Fermi level pinning at HfO2 and Ge interface. [Copyright &y& Elsevier]

Abstract: In this study, the nano-scale epi-Ge/Si fabrication and the Schottky junction source/drain manufacture with Ni incorporation are demonstrated. The Ni Schottky junction formation by laser annealing (LA) and rapid thermal annealing, as well as the barrier height and interface characteristics, are discussed. Improvement in the density of interface trap (Dit) can be achieved by LA; this technology enhances the opportunity of high Ge concentration SiGe channel to play a part in the next-generation complementary metal-oxide-semiconductor applications. [Copyright &y& Elsevier]

Abstract: Low-temperature (~250°C) layer exchange crystallization of poly-Si1− x Ge x (x =1–0) films on insulators has been investigated for realization of advanced flexible devices. We propose utilization of Au as catalyst to enhance the crystallization at low temperatures. By annealing (~250°C, 20h) of the a-Si1− x Ge x (x =1–0)/Au stacked structures formed on insulating substrates, the SiGe and Au layers exchange their positions, and Au/poly-SiGe stacked structures are obtained. The Ge fractions of the obtained poly-SiGe layers are identical to that of the initial a-SiGe layers, and there is no Si or Ge segregation. This low temperature crystallization technique enables poly-SiGe films on plastic substrates, which are essential to realize advanced flexible devices. [Copyright &y& Elsevier]

Abstract: Strain-induced enhancement of carrier mobility is essential for achieving high-speed transistors. The effects of thermal-annealing (temperature: 400–1150°C) and ultraviolet (UV) laser-annealing (wavelength: 248nm, temperature: 30–400°C) on strain-enhancement in Si-pillars covered with Si3N4 stress-liners by plasma-enhanced chemical vapor deposition are investigated. Before annealing, the Si3N4 stress-liners induce a tensile strain (~0.5%) in Si. After thermal-annealing (>800°C), the strain becomes highly compressive (> ~0.4%), because of dehydrogenation-induced structural relaxation in Si3N4 films. On the other hand, the tensile strain becomes large (>~0.7%) after UV laser-annealing at 400°C, due to non-equilibrium dehydrogenation in Si3N4 films. This strain-enhancement technique is useful for the realization of advanced high-speed three-dimensional transistors. [Copyright &y& Elsevier]

Abstract: The effect of thermal heat treatment on carbon in in-situ phosphorous-doped silicon-carbon is studied as a function of annealing temperature and type. Films of 0 to 2% carbon were deposited using cyclic chemical vapor deposition at reduced pressures. Secondary ion-mass spectroscopy and high-resolution X-ray diffraction were employed to extract the total and substitutional carbon concentration in samples with phosphorous levels of mid-1020 cm-3. It was found that millisecond laser annealing drastically improves substitutionality while high thermal budget treatments (furnace, rapid-thermal, or spike annealing) resulted in an almost complete loss of substitutional carbon, independent of preceding or subsequent laser heat treatments. [Copyright &y& Elsevier]