Microstructure Characterization of Hydrogenated Amorphous Silicon Films by Rare Gas Effusion Studies

2001 ◽  
Vol 664 ◽  
Author(s):  
Wolfhard Beyer

ABSTRACTThe effusion of the rare gases neon and helium, as well as of hydrogen, was studied for plasma deposited (boron-doped and undoped) hydrogenated amorphous silicon films, grown at various substrate temperatures. Rare gas atoms were incorporated into the material during the growth process or by ion implantation. The results suggest that helium and neon effusion spectra give information on the material microstructure.

2005 ◽  
Vol 864 ◽  
Author(s):  
F. Kail ◽  
A. Hadjadj ◽  
P. Roca i Cabarrocas

AbstractWe have studied the evolution of the structure of boron-doped hydrogenated amorphous silicon films exposed to a hydrogen plasma. From the early stages of exposure, hydrogen diffuses and forms a thick H-rich subsurface. At longer times, hydrogen plasma leads to the formation of a microcrystalline layer via chemical transport without crystallization of the initial layer. We observe that the hydrogen content increases in the films during a plasma exposure and once the microcrystalline layer is formed hydrogen diffuses out of the sample accompanied with a decrease in the boron content. This effect can be attributed to the electric field developed within the heterojunction a-Si:H/μc-Si:H that drives the positively charged hydrogen atoms in the boron-doped layer towards the μc-Si:H layer.


2013 ◽  
Vol 1536 ◽  
pp. 175-180 ◽  
Author(s):  
W. Beyer ◽  
W. Hilgers ◽  
D. Lennartz ◽  
F.C. Maier ◽  
N.H. Nickel ◽  
...  

ABSTRACTAn important property of thin film silicon and related materials is the microstructure which may involve the presence of interconnected and isolated voids. We report on effusion measurements of implanted helium (He) to detect such voids. Several series of hydrogenated and unhydrogenated amorphous silicon films prepared by the methods of plasma deposition, hot wire deposition and vacuum evaporation were investigated. The results show common features like a He effusion peak at low temperatures attributed to He out-diffusion through a compact material or through interconnected voids, and a He effusion peak at high temperatures attributed to He trapped in isolated voids. While undoped plasma-grown device-grade hydrogenated amorphous silicon (a-Si:H) films show a rather low concentration of such isolated voids, its concentration can be rather high in doped a-Si:H, in unhydrogenated evaporated material and others.


1991 ◽  
Vol 79 (8) ◽  
pp. 687-691 ◽  
Author(s):  
K.C. Nandi ◽  
D. Mukherjee ◽  
A.K. Biswas ◽  
H.N. Acharya

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