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Title: Deposition of Photosensitive Hydrogenated Amorphous Silicon-Germanium Films with a Tantalum Hot Wire

Abstract

No abstract prepared.

Authors:
; ; ; ;
Publication Date:
Research Org.:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
885108
DOE Contract Number:
AC36-99-GO10337
Resource Type:
Journal Article
Resource Relation:
Journal Name: Thin Solid Films; Journal Issue: 1-22006
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 36 MATERIALS SCIENCE; DEPOSITION; TANTALUM; SOLAR ENERGY; MATERIALS; AMORPHOUS SILICON-GERMANIUM FILMS; HOT-WIRE CHEMICAL VAPOR DEPOSITION (HWCVD); OPTICAL BANDGAP; TAUC BANDGAP; PHOTO-TO-DARK CONDUCTIVITY RATIO; PHOTOSENSITIVITY; PHOTON ABSORPTION COEFFICIENT; Solar Energy - Photovoltaics; Silicon Materials and Devices

Citation Formats

Xu, Y., Mahan, A. H., Gedvilas, L. M., Reedy, R. C., and Branz, H. M. Deposition of Photosensitive Hydrogenated Amorphous Silicon-Germanium Films with a Tantalum Hot Wire. United States: N. p., 2006. Web. doi:10.1016/j.tsf.2005.07.171.
Xu, Y., Mahan, A. H., Gedvilas, L. M., Reedy, R. C., & Branz, H. M. Deposition of Photosensitive Hydrogenated Amorphous Silicon-Germanium Films with a Tantalum Hot Wire. United States. doi:10.1016/j.tsf.2005.07.171.
Xu, Y., Mahan, A. H., Gedvilas, L. M., Reedy, R. C., and Branz, H. M. Sun . "Deposition of Photosensitive Hydrogenated Amorphous Silicon-Germanium Films with a Tantalum Hot Wire". United States. doi:10.1016/j.tsf.2005.07.171.
@article{osti_885108,
title = {Deposition of Photosensitive Hydrogenated Amorphous Silicon-Germanium Films with a Tantalum Hot Wire},
author = {Xu, Y. and Mahan, A. H. and Gedvilas, L. M. and Reedy, R. C. and Branz, H. M.},
abstractNote = {No abstract prepared.},
doi = {10.1016/j.tsf.2005.07.171},
journal = {Thin Solid Films},
number = 1-22006,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • Hydrogenated amorphous-silicon (a-Si:H) is grown by hot-wire chemical vapor deposition (HWCVD) at deposition rates (R{sub d}) exceeding 140 Aa/s ({similar_to}0.8 {mu}m/min). These high rates are achieved by using multiple filaments and deposition conditions different than those used to produce our standard 20 Aa/s material. With proper deposition parameter optimization, an AM1.5 photo-to-dark-conductivity ratio of 10{sup 5} is maintained at an R{sub d} up to 130 Aa/s, beyond which it decreases. In addition, the first saturated defect densities of high R{sub d} a-Si:H films are presented. These saturated defected densities are similar to those of the best HWCVD films deposited atmore » 5{endash}8 Aa/s, and are invariant with R{sub d} up to 130 Aa/s. {copyright} 2001 American Institute of Physics.« less
  • Intrinsic hydrogenated amorphous silicon (a-Si:H) has been deposited using a hot tungsten filament in pure silane to drive the deposition chemistry{emdash}the {open_quotes}hot-wire{close_quotes} deposition method. The electronic and infrared properties of the film have been measured as a function of deposition parameters, leading to three principal conclusions. First, to obtain a high quality material, the Si atoms evaporated from the filament (distance L from the substrate) must react with silane (density n{sub s}) before reaching the substrate; this requires n{sub s}L greater than a critical value. Second, radical-radical reactions cause deterioration of film properties at high values of G(n{sub s}L),{sup 3}more » where G is the film growth rate; this requires G(n{sub s}L){sup 3} less than a critical value. Finally, the film quality is a function of G, and as G is increased the substrate temperature must be correspondingly increased to obtain high film quality. By optimizing these parameters, we have produced films with excellent electronic properties (e.g., ambipolar diffusion length {gt}200 nm) at {gt}5 nm/s deposition rate. Based on these insights, formulas are also given for optimizing film properties in multiple-filament geometries and in diluted silane. {copyright} {ital 1997 American Institute of Physics.}« less
  • Intrinsic hydrogenated amorphous silicon (a-Si:H) has been deposited using a hot tungsten filament in pure silane to drive the deposition chemistry--the ''hot-wire'' deposition method. The electronic and infrared properties of the film have been measured as a function of deposition parameters, leading to three principal conclusions. First, to obtain a high quality material, the Si atoms evaporated from the filament (distance L from the substrate) must react with silane (density ns) before reaching the substrate; this requires nsL greater than a critical value. Second, radical-radical reactions cause deterioration of film properties at high values of G(nsL),3 where G is themore » film growth rate; this requires G(nsL)3 less than a critical value. Finally, the film quality is a function of G, and as G is increased the substrate temperature must be correspondingly increased to obtain high film quality. By optimizing these parameters, we have produced films with excellent electronic properties (e.g., ambipolar diffusion length >200 nm) at >5 nm/s deposition rate. Based on these insights, formulas are also given for optimizing film properties in multiple-filament geometries and in diluted silane.« less
  • Hydrogenated amorphous-silicon (a-Si:H) is grown by hot-wire chemical vapor deposition (HWCVD) at deposition rates (R{sub d}) exceeding 140 {angstrom}/s ({approx}0.8 {mu}m/min). These high rates are achieved by using multiple filaments and deposition conditions different than those used to produce our standard 20 {angstrom}/s material. With proper deposition parameter optimization, an AM1.5 photo-to-dark-conductivity ratio of 10{sup 5} is maintained at an R{sub d} up to 130 {angstrom}/s, beyond which it decreases. In addition, the first saturated defect densities of high R{sub d} a-Si:H films are presented. These saturated defected densities are similar to those of the best HWCVD films deposited atmore » 5--8 {angstrom}/s, and are invariant with R{sub d} up to 130 {angstrom}/s.« less