On the Role of Surface Diffusion and Its Relation to the Hydrogen Incorporation During Hydrogenated Amorphous Silicon Growth

2003 ◽  
Vol 762 ◽  
Author(s):  
A.H.M. Smets ◽  
W.M.M. Kessels ◽  
M.C.M. van de Sanden
Keyword(s):  
Activation Energy ◽  
Amorphous Silicon ◽  
Surface Diffusion ◽  
Diffusion Processes ◽  
Growth Parameters ◽  
Hydrogenated Amorphous Silicon ◽  
Hydrogen Incorporation ◽  
Silicon Growth ◽  
Surface Diffusion Processes ◽  
Hydrogenated Amorphous

AbstractThe incorporation of hydrogen in vacancies and at void surfaces during hydrogenated amorphous silicon growth from a remote expanding thermal plasma (ETP) is systematically studied by variation of the mass growth flux Γa-Si:H and substrate temperatureTsub. An evident relation between the void incorporation and the growth parameters Γa-Si:H andTsubhas been observed. We speculate on a possible relation with the surface diffusion processes during deposition. An activation energy for surface diffusion during a-Si:H growth of 0.8-1.1 eV is obtained using this assertion, similar to the activation energy deduced from surface roughness evolution studies. For compact films hydrogen is predominantly present at vacancies, and a possible relation with the hydrogen removal mechanism during deposition is discussed.

Reduction of the Defect Density in a-Si:H Deposited at ≤250°C

1993 ◽  
Vol 297 ◽  
Author(s):  
Hitoshi Nishio ◽  
Gautam Ganguly ◽  
Akihisa Matsuda
Keyword(s):  
Diffusion Coefficient ◽  
Amorphous Silicon ◽  
Surface Diffusion ◽  
Film Growth ◽  
Defect Density ◽  
Hydrogenated Amorphous Silicon ◽  
Device Fabrication ◽  
Surface Diffusion Coefficient ◽  
Hydrogenated Amorphous ◽  
Substrate Temperatures

We present a method to reduce the defect density in hydrogenated amorphous silicon (a-Si:H) deposited at low substrate temperatures similar to those used for device fabrication . Film-growth precursors are energized by a heated mesh to enhance their surface diffusion coefficient and this enables them to saturate more surface dangling bonds.

Calculations of SiH3 Diffusion and Growth Processes on a-Si:H Surfaces

2003 ◽  
Vol 762 ◽  
Author(s):  
P Vigneron ◽  
P W Peacock ◽  
K Xiong ◽  
J Robertson
Keyword(s):  
Total Energy ◽  
Amorphous Silicon ◽  
Surface Diffusion ◽  
Bound States ◽  
Smooth Surface ◽  
Hydrogenated Amorphous Silicon ◽  
Weakly Bound ◽  
Growth Site ◽  
Pseudopotential Calculations ◽  
Hydrogenated Amorphous

AbstractSurface diffusion of a growth species is needed to give the observed smooth surface of hydrogenated amorphous silicon (a-Si:H). But what diffuses, the weakly bound SiH3 radical on the hydrogenated surface, or the bound SiH3 at a growth site. Diffusion is complicated by the change in the surface termination of a-Si:H as temperature rises. We use total energy pseudopotential calculations on a variety of periodic Si:H surface configurations to show that it is the weakly bound SiH3 that diffuses. We provide an overall energy scheme of the bound states and transport levels of SiH3 on a-Si:H surfaces.

Isolated Voids in Amorphous Silicon and Related Materials Measured by Effusion of Implanted Helium

2012 ◽  
Vol 1426 ◽  
pp. 341-346 ◽  
Author(s):  
W. Beyer ◽  
W. Hilgers ◽  
D. Lennartz ◽  
F. Pennartz ◽  
P. Prunici
Keyword(s):  
Amorphous Silicon ◽  
Crystalline Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Vacuum Evaporation ◽  
Silicon Films ◽  
Preparation Process ◽  
Hydrogen Incorporation ◽  
Hydrogenated Amorphous ◽  
Deposition Techniques

ABSTRACTEffusion measurements of hydrogen and implanted helium are reported for (undoped) amorphous and crystalline Si:H and related materials. Effusion of helium observed at temperatures > 600°C is attributed to isolated voids present in the material from the preparation process. While rather high void densities are detected for amorphous silicon films prepared by such deposition techniques like vacuum evaporation or sputtering, much smaller densities are found for plasma grown hydrogenated amorphous silicon (a-Si:H). For device-grade a-Si:H, the density of cavities which can trap helium is estimated to be about 2x1018/cm3at most, suggesting that crystalline silicon type divacancies are not the major hydrogen incorporation site.

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