Preparation and Characterization of Highly Conductive (100 S/cm) Phosphorus Doped νc-Si:H Films Deposited Using the VHF-GD Technique

1989 ◽  
Vol 164 ◽  
Author(s):  
Kshem Prasad ◽  
F. Finger ◽  
H. Curtins ◽  
A. Shah ◽  
J. Bauman

AbstractWe report on the preparation and characterization of phosphorus doped gc-Si:H films produced by the very high frequency glow discharge (VHF-GD) at a plasma excitation frequency of 70 MHz. We present a systematic study of the deposition parameters i.e. hydrogen dilution of silane, VHF power density, gas phase doping ratio and deposition temperature and their influences on the electrical and structural properties of the material. In contrast to 13.56 MHz GD the VHF plasma conditions favour microcrystalline formation at low power densities; the resulting conductivities are significantly higher than those obtained at 13.56 MHz.

1994 ◽  
Vol 358 ◽  
Author(s):  
P. Hapke ◽  
F. Finger ◽  
M. Luysberg ◽  
R. Carius ◽  
H. Wagner

ABSTRACTThe growth mechanism and material properties of -type µc-Si:H prepared with plasma enhanced chemical vapour deposition in the very high frequency range is investigated. By increasing the plasma excitation frequency the grain size, deposition rate and Hall mobility can be simultaneously increased without having to adjust other deposition parameters in particular the temperature. This effect is explained by an enhanced selective etching of amorphous tissue and grain boundary regions together with a sufficient supply of growth species at high frequency plasmas.


1994 ◽  
Vol 336 ◽  
Author(s):  
G. Crovini ◽  
F. Demichelis ◽  
C.F. Pirri ◽  
E. Tresso ◽  
J. Meier ◽  
...  

ABSTRACTThe Very High Frequency (70 MHz) PECVD has recently proven its ability to produce Amorphous silicon with high deposition rates (10 Å/s) without affecting the quality of the Material. A comparative study of the optoelectronic properties of undoped silicon carbon alloys produced by Very High Frequency and by conventional RF (13.56 MHz) is carried out. Conductivity, infrared absorption, optical transmission and deep defect densities via PDS and ESR have been Measured. Deposition parameters under study aie methane fraction and hydrogen dilution. In contrast to conventional PECVD, we observe for VHF depositions an increase of the deposition rate with the addition of Methane. Larger energy gap and smaller Urbach energy values seem to indicate a better incorporation of carbon in the VHF case. A study of the degradation induced by light is also presented.


2001 ◽  
Vol 16 (7) ◽  
pp. 2130-2135
Author(s):  
Tapati Jana ◽  
Arup Dasgupta ◽  
Swati Ray

We developed p-type μc-silicon carbon alloy thin films by the very high frequency plasma-enhanced chemical vapour deposition technique using a SiH4, H2, CH4, and B2H6 gas mixture at low power (55 mW/cm2) and low substrate temperatures (150–250 °C). Effects of substrate temperature and plasma excitation frequency on the optoelectronic and structural properties of the films were studied. A film with conductivity 5.75 Scm−1 and 1.93 eV optical gap (E04) was obtained at a low substrate temperature of 200 °C using 63.75 MHz plasma frequency. The crystalline volume fractions of the films were estimated from the Raman spectra. We observed that crystallinity in silicon carbon alloy films depends critically on plasma excitation frequency. When higher power (117 mW/cm2) at 180 °C with 66 MHz frequency was applied, the deposition rate of the film increased to 50.7 Å/min without any significant change in optoelectronic properties.


2002 ◽  
Vol 16 (28n29) ◽  
pp. 4475-4478 ◽  
Author(s):  
HUIDONG YANG ◽  
CHUNYA WU ◽  
SHAOZHENG XIONG ◽  
YAOHUA MAI ◽  
HONGBO LI ◽  
...  

The intensities of SiH*, [Formula: see text] and H* of VHF-GD for depositing μc-Si:H were much higher than those of RF-GD for depositing a-Si:H. The SiH* intensity of VHF-GD became higher than its Si* intensity as the hydrogen dilution ratio decreased. The influences of the hydrogen dilution ratio on the plasma optical emission spectra also depended on the reaction pressure, the excitation power as well as the excitation frequency.


2010 ◽  
Vol 663-665 ◽  
pp. 1171-1174 ◽  
Author(s):  
Yan Qing Guo ◽  
Rui Huang ◽  
Jie Song ◽  
Xiang Wang ◽  
Yi Xiong Zhang

Nanocrystalline silicon films have been fabricated from SiH4 diluted with H2 in very high frequency (40.68 MHz) plasma enhanced chemical vapor deposition system at low temperatures (250oC). The influence of pressure on the structural properties of nanocrystalline silicon films has been investigated. The experimental results reveal that a very high hydrogen dilution is needed to crystallize the film grown at high pressure. If the hydrogen dilution is not high enough, the film could also be crystallized through lowering the pressure. Furthermore, the crystallinity and grain size increase with decreasing the pressure. These results could be attributed to the increase of ion bombardment energy and the higher atomic hydrogen flux toward the growing film surface at lower pressures.


2000 ◽  
Vol 638 ◽  
Author(s):  
K. Nishiguchi ◽  
X. Zhao ◽  
S. Oda

AbstractA cold electron emitter has been made from nanocrystalline silicon (nc-Si) dots. Nc-Si dots are formed in the gas phase by very-high-frequency (VHF) plasma enhanced chemical vapor deposition (CVD). Electrons, accelerated by electric field, are ballistically transported through nc-Si and SiO2, then extracted into vacuum. Electron emission efficiency is optimized through varying nc-Si film thickness, surface roughness, and by short thermal oxidation.


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