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In inverted perovskite solar cells, the [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/Ag back interface is quite important because serious recombination occurs and H2O/O2 directly attacks this interface to induce device instability. Here, bi-functional dipole layers are applied at the interface aiming at improving the charge transport and device stability simultaneously. Silane with -CF3 end group anchored on the PCBM surface induces more effective dipole effect than that with (CH2)7-CH3 end functional silane, bending the interface energy level to promote electron transport and reduce recombination. The hydrophobic nature of -CF3 also enhances the durability of the device. This work highlights the back surface dipole management method to achieve efficient and stable perovskite solar cells. [ABSTRACT FROM AUTHOR]

The band-alignment of atomic layer deposited (ALD)-HfO2/Al0.25Ga0.75N was studied by high resolution x-ray photoelectron spectroscopy measurements for both the non-passivated and SiH4 passivated AlGaN surfaces. The valence band offset and the conduction band offset for the ALD-HfO2/Al0.25Ga0.75N interface were found to be 0.43 eV and 1.47 eV, respectively, for the non-passivated sample, and 0.59 eV and 1.31 eV, respectively, for the SiH4-passivated sample. The difference in the band alignment is dominated by the band bending or band shift in the AlGaN substrate as a result of the different interlayers formed by the two surface preparations. [ABSTRACT FROM AUTHOR]

We report on GaN n-type doping using silane, germane, and isobutylgermane as Si and Ge dopants, respectively. A significant increase in tensile stress during growth is observed for Si doped samples while this is not the case for Ge doping. In addition, Ge can be doped up to 2.9 × 1020 cm-3, while Si doping leads to 3-D growth already at concentrations around 1.9 × 1019 cm-3. The free carrier concentration was determined by Hall-effect measurements, crystal quality, and structural properties by x-ray diffraction measurements. Additionally, secondary ion mass spectroscopy and Raman measurements were performed demonstrating the high material quality of Ge doped samples. [ABSTRACT FROM AUTHOR]

Heat flux microsensor-a thermopile with millisecond response time-was employed for direct measurements of total energy flux to a floated surface in a dusty rf discharge. The measurements were performed in silane-hydrogen plasmas at discharge conditions close to those used for the growth of polymorphous silicon films. At rf power between 10 and 50 W, the measured energy flux was in the range of 20-250 mW/cm2. Due to fast time response, the thermopile was also capable of tracing the dynamics of nanoparticle growth. A significant decrease (about 30%) in the energy flux was observed during the agglomeration phase. [ABSTRACT FROM AUTHOR]

In silicon heterojunction solar cells, thin amorphous silicon layers passivate the crystalline silicon wafer surfaces. By using in situ diagnostics during plasma-enhanced chemical vapor deposition (PECVD), the authors report how the passivation quality of such layers directly relate to the plasma conditions. Good interface passivation is obtained from highly depleted silane plasmas. Based upon this finding, layers deposited in a large-area very high frequency (40.68 MHz) PECVD reactor were optimized for heterojunction solar cells, yielding aperture efficiencies up to 20.3% on 4 cm2 cells. [ABSTRACT FROM AUTHOR]

Based on the nonequilibrium Green's function method combined with the density functional theory, the properties of a silane chain doped with phosphorus and boron atoms connected to two Au electrodes are investigated. It has been found that a barrier similar to the p-n junction is formed in the molecule because of the different electronegativities of phosphorus and boron atoms. The electronic transport properties of two parallel silanes are also investigated when they are positioned between two identical electrodes. The results show that direct interactions between chains may strengthen the rectifying effect when their separation is set suitably. The rectifying effect may disappear when their separation is altered to other values due to the splitting of the frontier molecular orbitals, which contributes to the formation of new transport channels. [ABSTRACT FROM AUTHOR]

We construct a phase diagram for silicon layer growth on (001) Si by hot-wire chemical vapor deposition (HWCVD), for rates from 10 to 150 nm/min and for substrate temperatures from 500 to 800 °C. Our results show that a mixed mono and dihydride surface termination during growth causes polycrystalline growth; some H-free sites are needed for epitaxy. For epitaxial films (T>620 °C), the dislocation density decreases with increasing growth temperature because of reduced O contamination of the surface. The best HWCVD epitaxial layers have dislocation densities of 105 cm-2. [ABSTRACT FROM AUTHOR]

We fabricated nonvolatile nanocrystal flash memory using Cu nanocrystals deposited at 110 °C by pulsed iodine-assisted chemical vapor deposition (CVD) as the charge storage elements. The Cu nanocrystals are deposited on 3-mercaptopropyltrimethoxysilane (MPTMS) coated SiO2 (4 nm) thermally grown on Si, followed by the coating of MPTMS on the Cu nanoparticles to immobilize the Cu atoms. This novel device structure is simply fabricated by pulsed CVD and exhibits a threshold voltage shift of 1.9 V after the application of a voltage pulse (erase: -14 V, 1 ms/program: 40 V, 1 ms) to the gate and has reliable data retention characteristics. [ABSTRACT FROM AUTHOR]

The silane dissociation efficiency, or depletion fraction, is an important plasma parameter by means of which the film growth rate and the amorphous-to-microcrystalline silicon transition regime can be monitored in situ. In this letter we implement a homebuilt quantum cascade laser-based absorption spectrometer to measure the silane dissociation efficiency in an industrial plasma-enhanced chemical vapor deposition system. This infrared laser-based diagnostic technique is compact, sensitive, and nonintrusive. Its resolution is good enough to resolve Doppler-broadened rotovibrational absorption lines of silane. The latter feature various absorption strengths, thereby enabling depletion measurements over a wide range of process conditions. [ABSTRACT FROM AUTHOR]

A joint theoretical and experimental analysis of the crystalline fraction in nanocrystalline films grown by low-energy plasma enhanced chemical vapor deposition is presented. The effect of key growth parameters such as temperature, silane flux, and hydrogen dilution ratio is analyzed and modeled at the atomic scale, introducing an environment-dependent crystallization probability. A very good agreement between experiments and theory is found, despite the use of a single fitting parameter. [ABSTRACT FROM AUTHOR]

Bimorph ferroelectric microcantilevers are fabricated at the locations of the interdomain walls of inversely poled lithium niobate. The cantilevers are excited via the piezoelectric effect using a rf voltage and the natural vibrations are observed via optical detection. The self-assembling layers of two different silanes are chemically deposited on the microcantilevers. The presence of the silane layers is detected by two independent methods: optical detection of a low frequency shift of cantilever natural vibrations and the analysis of Raman spectral lines from the Silane layers. Possible applications include smart biosensors in real time domains. [ABSTRACT FROM AUTHOR]

The authors investigate the dependence of the photoluminescence intensity ratio between the near-band-edge and the parasitic blue emission as a function of silane flow in n-type Al0.3Ga0.7N. It is found that when the silane flow rate is higher than 1.13×10-9 mol/min, the UV-to-blue ratio is a constant. When the silane flow rate is lower than 1.13×10-9 mol/min, the UV-to-blue ratio increases rapidly as the silane flow rate decreases. A theoretical model is proposed, which assumes that the parasitic blue emission is caused by an acceptorlike compensating native defect. The model is fully consistent with the experimental results. [ABSTRACT FROM AUTHOR]

The growth of silicon nanocrystals in high pressure and high dilution silane plasmas is investigated by using the temporal evolution of the self-bias on the radio frequency electrode and transmission electron microscopy. A square-wave-modulated plasma was used in order to control the growth of monodispersed nanoparticles with sizes smaller than 12 nm. To this end, the plasma on time was kept below 1 s. The radial growth rate of nanoparticles was varied in the range from 7.5 to 75 nm/s by changing silane partial pressure. Nanoparticles grown in silane-helium discharges have been found amorphous while they are crystalline in silane-hydrogen-argon discharges. Surprisingly, the crystallization in the gaseous phase does not depend on how slow or fast the particles grow but on the presence of atomic hydrogen. [ABSTRACT FROM AUTHOR]

Using scanning tunneling microscopy, the authors show that uniform-size Mo-encapsulating Si clusters, MoSin, were synthesized on Si (111)-7×7 surfaces by the reaction between SiH4 and Mo atoms deposited on the surface followed by thermal annealing at 600 °C. Comparing observed images with ab initio structure calculations indicates that n=6. According to scanning tunneling spectroscopy measurements, the MoSin cluster has a semiconducting energy gap of approximately 0.3 eV, indicating that the metallic electronic state of the 7×7 surface can be locally modified by formation of the MoSin cluster. [ABSTRACT FROM AUTHOR]

The photo-leakage-current (IPLC) characteristic of F incorporated a-Si:H thin film transistor (TFT) has been studied. The device activation energy (Ea) of a-Si:H(:F) TFTs is higher than those of typical a-Si:H TFTs, and resulted in the shift down of Fermi level in a-Si:H(:F). Experimental results show that the IPLC of a-Si:H(:F) TFTs is smaller than that of conventional a-Si:H TFTs in the density of states limited region, stemmed from the higher recombination centers present in a-Si:H(:F) material. However, the higher IPLC is observed in the hole conduction region, resulted from the larger Ea in the a-Si:H(:F) TFTs. [ABSTRACT FROM AUTHOR]

A low operating electric field has been achieved on silicon nanowires grown on carbon cloth. The silicon nanowires were grown on carbon cloth via the vapor-liquid-solid reaction using silane gas as the silicon source and gold as catalyst from the decomposition of hydrogen gold tetrachloride. An emission current density of 1 mA/cm2 was obtained at an operating electric field of 0.7 V/μm. Such low field is resulted from a high field enhancement factor of 6.1×104 due to the combined effects of the high intrinsic aspect ratio of silicon nanowires and the woven geometry of carbon cloth. Such results may lead silicon nanowire field emitters to practical applications in vacuum microelectronic devices including microwave devices. [ABSTRACT FROM AUTHOR]

The effects of γ-aminopropyltriethoxy silane coupling agent on electrical properties in multiwall carbon nanotube/methylvinyl silicone rubber nanocomposites were studied. The results showed that the modified nanotubes could be dispersed homogeneously and that they had a tight bonding with the rubber matrix. The concentration of coupling agent played a crucial role in deciding the conductivity and the electrical properties of the nanocomposites exhibited strong dependences on temperature and pressure. Dependences of electrical properties on temperature and pressure were also improved by increasing the content of coupling agent. [ABSTRACT FROM AUTHOR]

A combined cross-sectional transmission electron microscope (XTEM) and atomic force microscope (AFM) study of a hydrogen to silane dilution series of thin silicon films deposited by very high frequency plasma enhanced chemical vapor deposition at a substrate temperature that is low enough (39 °C) to neglect the role of the surface diffusion in the growth process is reported. XTEM images of a mixed amorphous/microcrystalline layer reveal a structure of isolated conically shaped crystalline conglomerates (surface diameter ∼570±75 nm) embedded in an amorphous phase of columns with diameters of ∼51±3 nm. Detailed closeups of these crystallites, combined with AFM images of the hydrogen dilution dependent evolution of the surface, reveal similarities between the nucleation of amorphous and crystalline columnar structures at this low substrate temperature. [ABSTRACT FROM AUTHOR]

We report an efficient blue light-emitting diode (LED) using N, N′-bis(1-naphthyl)-N, N′-diphenylbenzidine as an emitting layer and tetra(β-naphthyl)silane (TNS) as a hole-blocking layer (HBL). We find that the hole-blocking performance, thermal stability, and film-forming ability of TNS are improved over those of the prototypical hole-blocking material 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP). The device that used TNS as the HBL exhibits a narrower light emission and higher current efficiency (2.5 cd/A) as compared with the device containing BCP as the HBL. TNS should be promising as an excellent hole-blocking layer in LEDs. [ABSTRACT FROM AUTHOR]

We have measured the growth rate of silicon nanowires (SiNWs), which were grown at temperatures between 365 and 495 °C via the vapor-liquid-solid (VLS) mechanism. We grew SiNWs using gold as catalysts and monosilane (SiH4) as a vapor phase reactant. Observing SiNWs by means of transmission electron microscopy, we have found that SiNWs with smaller diameters grow slower than those with larger ones, and the critical diameter at which growth stops completely exists. We have estimated the critical diameter of SiNWs to be about 2 nm. We have also measured the temperature dependence of the growth rate of SiNWs and estimated the activation energy of the growth of SiNWs to be 230 kJ/mol. [ABSTRACT FROM AUTHOR]

Preparation of microcrystalline silicon for solar cell applications is investigated under high-pressure, high-power conditions with plasma-enhanced chemical vapor deposition at 95 MHz. It is found that the deposition rate depends mainly on the amount of silane in the reaction zone. Changes in the discharge power affect the deposition rate very little. This points to silane depletion under these process conditions. The amount of H radicals, on the other hand, increases with increasing discharge power and leads to structure changes of the material. Making use of this effect, optimum phase mixture material at the transition from highly crystalline to amorphous growth can be deposited at considerably higher deposition rates without loss in solar cell performance. [ABSTRACT FROM AUTHOR]

Low-temperature Si growth on the atomic-layer order nitrided Si(100) surface with N amount of 1-6×10[sup 14] cm[sup -2] formed by NH[sub 3] reaction at 400°C were investigated using an ultraclean low-pressure chemical vapor deposition system. The epitaxial growth of Si film on the nitrided Si(100) with the initial N amount as high as about 3 × 10[sup 14] cm[sup -2] is realized at 500 °C, although the film becomes amorphous in the case at the initial surface N amount of 6 × 10[sup 14] cm[sup -2]. By the analysis of the x-ray photoelectron spectroscopy, it is observed that the surface structure of the atomic-layer order nitrided Si(100) is changed into Si[sub 3]N[sub 4] structure by the increase of the surface N amount. It is suggested that the crystallinity of Si film deposited on the atomic-layer order nitrided Si(100) is degraded by the existence of Si[sub 3]N[sub 4] structure. Depth profile of N atomic-layer doped Si film clearly shows that most of the N atoms are confined within about 1-nm-thick region. [ABSTRACT FROM AUTHOR]

Thin films of hydrogenated amorphous silicon (a-Si:H) prepared by plasma-enhanced chemical vapor deposition with 10% SiH[sub 4] in hydrogen have been studied concerning the effect of film thickness on the hydrogen concentration, interconnected void network and mechanical stress. The hydrogen concentration was determined by nuclear reaction analysis. The interconnected void network was studied by the method of ion exchange in glass substrate. The films were prepared at a substrate temperature in the range of 150–270 °C. The results show that at the substrate temperature of 150 °C the film starts to grow with an extensive void network, and its structural improvement with thickness is manifested by an increase of the film density. In contrast, at 270 °C the film starts to grow with a dense structure, and its improvement is manifested by an increase of the intrinsic compressive stress. The hydrogen concentration does not depend on the film thickness at any substrate temperature. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Radicals produced by the hot wire-induced decomposition of silane have been identified using vacuum ultraviolet single photon ionization (SPI). This laser-based technique uses 118 nm photons (10.5 eV) to ionize gas phase species; the resulting photoions are detected using time-of-flight mass spectrometry. The major silicon-containing gas-phase species identified by SPI during hot-wire activation of silane gas are Si, SiH[sub 3], and Si[sub 2]H[sub 6]. These results demonstrate that single photon ionization can be a powerful probe for in situ, real-time detection of multiple species in hot wire chemical vapor deposition. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Neutral higher silane molecules in silane radio frequency glow discharge plasmas are investigated using photoionization mass spectroscopy at various radio frequency (rf) powers and total pressures. Densities of higher silane molecules increase with rf power up to 10 W, and then decrease at 10–100 W. The reduction of the neutral higher silane molecules at high rf power suggests that these molecules contribute to the particle formation through secondary reactions in the plasma. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A new device is described for continuous conversion of pure silane into disilane in yields up to 40%. The device was used in line with an amorphous silicon deposition system to grow 1-μm-thick films at 300 °C. The minority-carrier diffusion length measured on one of these films was 0.3 μm at one sun illumination. The device can also be used with a synthesis station to collect large quantities of pure disilane. The absence of hydrocarbons, chlorosilanes, and siloxanes at the 10–100 ppm levels was established by analysis of a collected disilane sample. [ABSTRACT FROM AUTHOR]

A capacitively coupled, rf glow discharge of silane in argon was studied to determine the spatial dependence of particle light scattering. Light scattering from a pulsed laser at 500 nm shows sharp spatial peaks of scattered intensity near the electrodes. These scattering peaks are correlated with the plasma sheath edges because they exhibit spatial changes with discharge pressure characterized by a constant product of pressure and distance from the electrode. Light scattering at various silane mole fractions and gas flow rates is compatible with concepts of particle growth in sharp spatial zones near the plasma sheaths. [ABSTRACT FROM AUTHOR]

The reactive species SiH2 has been directly observed in dc glow discharges using the technique of frequency modulation absorption spectroscopy. The spatial distribution of SiH2 in the discharge and the relative amounts of SiH2 in silane and disilane discharges have been measured. [ABSTRACT FROM AUTHOR]

High speed preparation of A1/nip/SnO2/indium tin oxide/Glass type amorphous Si solar cells from disilane is presented with emphasis on the boron doping profile during the intrinsic layer deposition. It was found that the cell characteristics strongly depend on the doping level and the profile of B2H6, and 8.05% and 6.85% conversion efficiencies were obtained with a linear graded doping profile at the deposition rates of 15 and 30 Å/s, respectively. [ABSTRACT FROM AUTHOR]

Disilane (Si2H6) is presented as a new silicon doping source in the metalorganic chemical vapor deposition of GaAs together with comparison results obtained using the conventional silane (SiH4) doping source. The doping characteristics of disilane were studied over a wide range of growth conditions: temperature, gas phase stoichiometry, and disilane concentration in the growth ambient. Silicon incorporation by means of disilane pyrolysis showed no temperature dependence, in sharp contrast to the strong temperature activated dependence found when employing silane. The decomposition reaction of disilane proved to be very efficient, reducing the amount of dopant gas required by about two orders of magnitude at the lower growth temperatures. Electrical measurements on disilane-doped GaAs yield the same high mobilities as obtained in silane-doped GaAs films, indicative of low compensation. [ABSTRACT FROM AUTHOR]

A novel and economical method for the preparation of the hydrogenated amorphous silicon films by glow discharge composition of silane in two reactors connected in cascade is presented. Whereas the films obtained from the first reactor have nearly the same dark and photoconductivity as reported in literature, those from the second reactor exhibit four orders less dark conductivity and one order less photoconductivity for the same deposition conditions. [ABSTRACT FROM AUTHOR]

For the first time an intermediate chemical species, Si2, has been observed in the gas phase during the chemical vapor deposition of silicon from silane. This observation is inconsistent with previous theoretical models for silicon deposition, which assume that either thermodynamic equilibrium or surface kinetics determines the silicon deposition rate. It is consistent with the predictions of a new model for chemical vapor deposition by Coltrin et al., in which gas phase chemical kinetics play an important role in the deposition mechanism. The Si2 molecule could be a precursor to the nucleation of silicon particulates in the gas phase. [ABSTRACT FROM AUTHOR]

Examines the growing process and particle behavior in a helium-diluted silane radio frequency (rf) plasma using laser light scattering methods. Production of the particles around the rf electrode sheath edge; Suspension of the particles by an electrostatic force; Effectiveness of gas flow for particle motion.

Analyzes the reflection high-energy electron diffraction intensity oscillations during disilane gas source molecular beam epitaxy. Details of the observed oscillations; Limitation of the growth rate on silicon (100) surfaces; Indication of monohydride structure on silicon (111) surface.

Examines the heavily silicon-doped gallium arsenide grown by low-pressure metalorganic chemical vapor deposition. Use of tertiarybutylarsine and silane as dopant source gas; Origin of the compensating center; Dependence of electron concentration on growth temperature.

Investigates the contamination in silane radio frequency plasma due to the generated and suspended particles. Detection of powder by illumination of the reactor volume; Uses of the simple diagnostic for global, spatio-temporal powder dynamics; Details on the power modulation.

Examines the electric-field-enhanced photoscission of the silicon backbone in organopolysilane films. Effects of the prolonged ultraviolet light irradiation of the materials; Reversibility of the changes by annealing near the melting temperature; Causes of the photoscission of the silicon backbones.

The ultrafast photocarrier dynamics in polysilane alloys, amorphous (SiH2)n, has been studied using the picosecond photoinduced absorption (PA) technique. For excitation below the optical gap, the PA response decays exponentially and is faster at low temperatures. This is interpreted in terms of e-h geminate recombination in the small clusters (∼10 Å) of a-Si:H embedded in the polysilane matrix. The PA response with above-gap excitation is similar to that of conventional a-Si:H; it decays much slower in the form of a power law t -β (β<1), independent of spectral range between 1.4 and 2.2 eV. This shows that the e-h distance after above-gap photogeneration is larger than the size of the a-Si:H clusters. [ABSTRACT FROM AUTHOR]

A self-consistent quantitative analysis of recent kinetic data on the role of di- and trisilane in the plasma-induced deposition of amorphous silicon from monosilane confirms the conclusion that the dominant reactive intermediate responsible for the formation of di- and trisilane and, consequently, for the deposition of a high quality amorphous silicon is SiH2. The data show that the SiH3 radical may play only a negligible, if any, role in this process. [ABSTRACT FROM AUTHOR]

The rate of production of disilane (Si2H6) in silane (SiH4) plasmas by gas phase and surface-catalyzed processes is examined. The discussion is based on results from plasma chemistry and surface deposition computer models. The surface model simulates the adsorption of silane radicals from the plasma on a growing amorphous silicon film and the subsequent desorption from the surface of the nonadhering SiH3 radicals as Si2H6. The rate of generation of Si2H6 from the surface reactions is compared to the rate of generation due to plasma reactions. We find that for conditions which are typical of those used for deposition of amorphous silicon, production of disilane is likely dominated by surface-catalyzed processes. The rate of production, though, depends on the sticking coefficient of SiH3, which we find to be a function of plasma conditions. [ABSTRACT FROM AUTHOR]

The formation of silicon carbide powder in a 3% SiH4-3% CH4-Ar mixture was studied in a shock tube. The experiments were conducted at the temperature of 800–3650 K, pressures of 0.46–4.16 atm, and reaction times of 1–2 ms. The progress of reaction was monitored by the attenuation of a He-Ne (633 nm) laser beam. Powders collected at the end wall of the tube were identified to be β-SiC and at high temperatures contained particles having sizes up to 0.5 μm. The large particles had the form of thin single-crystal platelets with hexagonal and truncated triangular shapes. The transmitted laser light intensity as a function of reaction time exhibited a pronounced minimum at incident shock temperatures above 1700 K. A reaction model is proposed that explains the experimental observations. It is postulated that SiC particles are nucleated homogeneously, along with Si particles. The latter are etched by the products of methane pyrolysis and the chemical species formed by the etching add to the growth of SiC particles. [ABSTRACT FROM AUTHOR]

Time-resolved mass spectrometric data of the decay of monosilane concentration and of the formation and decay of disilane and trisilane are presented together with the silicon deposition rates measured under the same conditions. The data can be quantitatively explained by the mechanism involving, as a first step, the fragmentation of silane into SiH2 and H2, and deposition of a-Si via higher silanes which are formed by a fast insertion reaction of silene into gaseous silanes. Deposition via a SiH3 radical, which has been suggested by several groups, cannot explain the experimental data. [ABSTRACT FROM AUTHOR]

An ultraclean hot-wall low-pressure chemical vapor deposition (CVD) system was developed and Si films were deposited on single-crystal Si and SiO2 using ultraclean SiH4 and H2 gases in the temperature range 600–850 °C under an ultraclean environment. As a result of ultraclean processing, an incubation period of Si deposition only on SiO2 was found, and low-temperature Si selective deposition and epitaxy on Si were achieved without addition of HCl under deposition conditions where only nonselective polycrystalline Si growth could be obtained in conventional CVD systems. [ABSTRACT FROM AUTHOR]

Silicon dots have been produced by the decomposition of silane on Si layers deposited on quartz plates and irradiated by a cw Ar+ laser beam. The vertical deposition rate of Si dots was investigated as a function of irradiation time, output laser power, and silane pressure. The Si layer on quartz was first irradiated with the laser beam penetrating through the transparent quartz plate (back irradiation). The deposition of Si dots occurred by pyrolytic decomposition of ‘‘cold’’ silane molecules impinging on the laser heated area. When the surface of the Si layer on quartz was directly irradiated with the visible laser beam (front irradiation), the deposition of Si dots was accomplished at lower temperatures and involved an interaction of photons with reactive species. The kinetics of this photon-aided process is surface controlled and characterized by an apparent activation energy of about 38 kcal mol-1. [ABSTRACT FROM AUTHOR]

The apparatus and its preliminary results of gas source silicon molecular beam epitaxy are reported for the first time. In this study, silane (SiH4) was used as a source gas. A subchamber was designed to control the gas flow precisely. SiH4 exposure during the initial cleaning was effective in lowering the cleaning temperature and saving the cleaning time. Epitaxial silicon films grew uniformly on 4-in. wafers. There was no spitting defect on the epitaxial films. Moreover, selective epitaxial growth was realized using a patterned SiO2 mask. [ABSTRACT FROM AUTHOR]

Epitaxial growth of phosphorus-doped silicon deposited at 250 °C from a radio-frequency glow discharge from SiH4 is demonstrated by high-resolution electron microscopy (HREM) and spreading resistance profile measurements. Thin epitaxial films are present at the interface between (100) Si substrates and hydrogenated amorphous silicon. After recrystallization at 700 °C, single-crystal layers are obtained, in which HREM reveals extensive twinning. The fact that epitaxial growth can take place at 250 °C in a system with a background pressure of only 5×10-6 mbar can be attributed to the presence of species in the SiH4 plasma that reduce the native oxide and the use of HF in the cleaning procedure. [ABSTRACT FROM AUTHOR]