Low Temperature Deposition of Polycrystalline Silicon thin Films by Hot-Wire CVD

1995 ◽  
Vol 377 ◽  
Author(s):  
Shuangying Yu ◽  
Sadanand Deshpande ◽  
Erdogan Gulari ◽  
Jerzy Kanicki
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Growth Rate ◽  
Substrate Temperature ◽  
Flow Rate ◽  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
Hot Wire ◽  
Hydrogen Flow ◽  
Si Films

ABSTRACTIn this study, we have deposited polycrystalline silicon (poly-Si) thin films by hot-wire Chemical Vapor Deposition (CVD) using hydrogen and disilane as the reactive gases. We selectively activate hydrogen and let disilane bypass the hot tungsten filament assembly and enter the reactor downstream from hydrogen. This may provide a better process chemistry, and by this approach, we have deposited poly-Si films at a substrate temperature as low as 310°C and at a growth rate as high as 100 Å/min. The substrate temperature is more than 2000C lower and the growth rate is more than twice higher compared to those of LPCVD poly-Si films. The effect of hydrogen flow rate, disilane flow rate and substrate temperature on the deposition rate and structural properties of the polysilicon films are investigated. The deposited films are characterized by transmission electron microscopy, scanning electron microscopy, Raman spectroscopy and X-ray diffraction.

Growth of “New Form” of Polycrystalline Silicon Thin Films Synthesized by Hot Wire Chemical Vapor Deposition

2005 ◽  
Vol 862 ◽  
Author(s):  
A. R. Middya ◽  
J-J. Liang ◽  
K. Ghosh
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
Crystallographic Structure ◽  
Hot Wire ◽  
Silicon Thin Films ◽  
Vapor Deposition Technique ◽  
New Form

AbstractIn this work, we report on next-generation hot wire chemical vapor deposition technique, we call it ceramics hot-wire CVD. Using a new concept of rectangular ceramics filament holder and “confinement of thermal radiation from the filament”, a “new form” of polycrystalline silicon thin films has been developed at low temperature (˜ 250°C). The grains are found to be symmetrically distributed in array along the parallel lines, in (111) direction. On the surface of individual grains, “five-fold” and “six-fold” symmetries have been observed and we suspect that we developed “buckyball” type “giant silicon molecular solids” with different crystalline silicon lattice other than standard single-crystal silicon structure. We observed rarely found “icosaderal” symmetry in silicon thin films. This hypothesis has been supported by multiple Raman active transverse optical modes and the crystallographic structure analyzed by X-ray diffraction.

Fast Deposition of Polycrystalline Silicon Films by Hot-Wire CVD

1995 ◽  
Vol 377 ◽  
Author(s):  
A. R. Middya ◽  
A. Lloret ◽  
J. Perrin ◽  
J. Huc ◽  
J. L. Moncel ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Polycrystalline Silicon ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Hot Wire ◽  
Crystalline Orientation ◽  
Silicon Thin Films ◽  
Hydrogen Dilution ◽  
Si Films ◽  
Polycrystalline Silicon Films

ABSTRACTPolycrystalline silicon thin films have been deposited at fast growth rates (50 Å/s) by hotwire chemical vapour deposition (HW-CVD) from SiH4/H2 gas mixtures at low substrate temperature (400–500°C). The surface morphology of these films consists of 0.5 – 2.0μm dendritic grains as seen by electron microscopy. The films have a columnar morphology with grains starting from the substrate either on glass or c-Si. Even the 150 nm thick initial layer is polycrystalline. The preferential crystalline orientation of the poly-Si film is apparently not governed by the radiative source but strongly depends on the type and orientation of the substrate. A strong hydrogen dilution (>90%) of silane is essential to obtain poly-Si films with optimal crystalline structure.

Deposition of YSZ Thin Films by Liquid Fuel Combustion Chemical Vapor Deposition

2002 ◽  
Author(s):  
Zhigang Xu ◽  
Jag Sankar ◽  
Qiuming Wei ◽  
Jim Lua ◽  
Sergey Yamolenko ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Substrate Temperature ◽  
Vapor Deposition ◽  
Liquid Fuel ◽  
Film Growth ◽  
Early Stage ◽  
Chemical Vapor ◽  
Nucleation Density

Thin film of YSZ electrolyte is highly desired to reduce the electrical resistance in SOFCs. YSZ thin Films have been successfully produced using liquid fuel combustion chemical vapor deposition (CCVD) technique. Nucleation of the YSZ particles were investigated based on two processing parameters, i.e., substrate temperature and total-metal-concentration in the liquid fuel. An optimum substrate temperature was found for highest the nucleation density. The nucleation density was increased with the total-metal-concentration. Microstructure evolution of the YSZ particles in the early stage in film growth was also studied. It was found that the particle growth rate was linear with processing time, and the particle orientation was varying with the time in the early stage of the film processing. To enhance the film growth rate, the effect of thermophoresis was studied. By increase the temperature gradient towards substrate, the effect of thermophoresis was enhanced and the film growth is also increased.

Effect of SiH4 Flow Rates on the Structures and Properties of Si-Rich Silicon Nitride Films Prepared by Hot Wire Chemical Vapor Deposition

2019 ◽  
Vol 288 ◽  
pp. 135-139 ◽  
Author(s):  
Yan Sai Tian ◽  
Ai Ming Gao ◽  
Bing Qing Zhou
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Band Gap ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Light Transmittance ◽  
Silicon Cluster ◽  
Hot Wire

Silicon-rich silicon nitride thin films were deposited on the P type (100) of silicon and Corning7059 glass by hot-wire chemical vapor deposition method using SiH4 and NH3 as reaction gas source. The effects of SiH4 flow rate on the structures and optical properties of the thin films were studied under optimizing other deposition parameters. The structures, band gap width and surface morphology of the thin films were characterized by Fourier transform infrared absorption spectroscopy (FTIR), ultraviolet-visible (UV-VIS) light transmittance spectra and scanning electron microscope (SEM), respectively. The experiment results show that, with increasing of the SiH4 flow rate, the content of N and Si atoms in the thin films increases, and the Si-N bond density increases gradually, and the optical band gap of the films shows a trend of increasing. When the silane flow rate is less than 0.9sccm, there is no Si-H bond stretching vibration absorption peak, and silicon atoms mainly bond with nitrogen atoms. As the SiH4 flow rate decreases, silicon clusters embedded in silicon nitride matrix gradually become smaller. When SiH4 flow rate is 0.4sccm, we prepared the silicon cluster nanoparticles with an average diameter of about 50nm embedded in silicon nitride thin films matrix. Therefore, properly reduction of the SiH4 flow rate is favorable for preparing the smaller silicon cluster nanoparticles in silicon rich silicon nitride thin films. The results lay the foundation for the preparation of silicon quantum dots thin film materials.

Growth of SrS Thin Films by Atomic Layer Epitaxy

1991 ◽  
Vol 222 ◽  
Author(s):  
M. Leskela ◽  
L. Niinistö ◽  
E. Nykänen ◽  
P. Soininen ◽  
M. Tiitta
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Substrate Temperature ◽  
Flow Rate ◽  
Atomic Layer ◽  
Atomic Layer Epitaxy ◽  
Source Temperature ◽  
Large Size ◽  
Monolayer Growth ◽  
Purge Gas

ABSTRACTThe growth of strontium sulfide thin films in a flow-type Atomic Layer Epitaxy reactor from Sr(thd)2 (thd = 2,2,6,6-tetramethyl-3,5-heptanedione) and H2S has been studied. The growth is independent on flow rate and duration of the purge gas (N2) pulse and it does not depend on the Sr(thd)2 and H2S pulses either provided their amounts are sufficient to saturate the surface. The variables significantly affecting the growth rate are the substrate temperature and source temperature for Sr(thd)2. The observed lower than one monolayer growth rate is mainly due to the large size of the Sr(thd)2 molecule.

High-Growth Rate a-Si:H Deposited by Hot-Wire CVD

1994 ◽  
Vol 336 ◽  
Author(s):  
P. Brogueira ◽  
V. Chu ◽  
J.P. Conde
Keyword(s):  
Flow Rate ◽  
Chemical Vapor ◽  
High Growth ◽  
Dark Conductivity ◽  
High Growth Rate ◽  
Hot Wire ◽  
Tungsten Filament ◽  
Hydrogen Flow ◽  
Deposition Parameters ◽  
Pressure Regime

ABSTRACTWe present a study of the optoelectronic and structural properties of a-Si:H deposited by Hot-Wire chemical vapor deposition (HW-CVD) from SiH4 and H2 at “Medium” (Tfil ≃ 1500°C) and “high” (Tfil ≃ 1900 °C) filament temperatures. For each tungsten filament temperature regime, the following deposition parameters are varied: (i) pressure (p ∼ 10−2 — 0.5 Torr); (ii) substrate temperature (Tsub ∼ 180 — 270 °C); (iii) silane flow rate (FsiH4 ∼ 1 — 10 ccm) and (iv) hydrogen flow rate (FH2 ∼ 0 — 10 seem). Films deposited at Tfil ∼ 1900 °C in a low pressure regime (p ∼ 2.7 × 10−2Torr) using flows of 5 sccm for both H2 and SiH4 had high deposition rates (rd ∼ 8 Ås−1). These films showed an optical bandgap, E9Tauc ≃ 1.7 eV, a dark conductivity σd ∼ 10−8Scm−1 with an activation energy Eα,σd ≃ 0.8 eV, and photoconductivity σph ≥ 10−5Scm−1 (σph ∼ 10−5). Films deposited at Tju = 1500 °C and p ≃ 0.3 Torr, showed 1.7 < E9Tauc < 2 eV, 10−5 < σd < 10−3Scm−1, 0.2 < Eα,σ d < 0.5 eV and σph/Σd < 102. For the same Tfit and p ∼ 3 × 10−2 — 0.1 Torr, the films show 1.7 < E9Tauc < 2 eV, 10−3 < Σd < 10−1Scm−1 and σph/σd < 1. Films deposited using molybdenum and rhenium filaments at Tfil ≃ 1900 °C show E9Tauc ≃ 1.7 eV and σd ∼ σph ∼ 10−7Scm−1

Characterization of a‐SiNx Thin Film Deposited By Inductively Coupled Plasma Enhanced Chemical Vapor Deposition

1996 ◽  
Vol 446 ◽  
Author(s):  
Sang‐Soo Han ◽  
Byung‐Hyuk Jun ◽  
Kwangsoo No ◽  
Byeong‐Soo Bae
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Substrate Temperature ◽  
Flow Rate ◽  
Hydrogen Content ◽  
Vapor Deposition ◽  
Inductively Coupled Plasma ◽  
Chemical Vapor ◽  
Rf Power ◽  
Inductively Coupled

AbstractSilicon nitride thin films are deposited at low temperature using the inductively coupled plasma enhanced chemical vapor deposition.(ICP‐CVD) N2 and SiH4 gases are used as reactant gases for deposition of silicon nitride thin films with low hydrogen content. Composition, refractive index, and hydrogen content of the films were examined with variation of N2 flow rate, RF power and substrate temperature. As N2 flow rate and RF power increase and substrate temperature is lowered, N/Si ratio is reduced producing higher refractive index of the film. Hydrogen content of the films is calculated by FTIR spectroscopy and is much less than those of the films deposited by conventional PECVD using SiH4/N2 gases since N2 gas is used instead of NH3 gas. Total hydrogen content is constant regardless of RF Power and N2 flow rate. However, the hydrogen content decreases with increasing substrate temperature due to the release of hydrogen at high temperature.

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