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Low Defect Density Microcrystalline-Si Deposited by the Hot Wire Technique

Published online by Cambridge University Press:  10 February 2011

A. H. Mahan
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
M. Vanecek
Affiliation:
Insitiute of Physics, Academy of Sciences of the Czech Republic, Prague 6, CZ-16253 Czech Republic
A. Poruba
Affiliation:
Insitiute of Physics, Academy of Sciences of the Czech Republic, Prague 6, CZ-16253 Czech Republic
V. Vorlicek
Affiliation:
Insitiute of Physics, Academy of Sciences of the Czech Republic, Prague 6, CZ-16253 Czech Republic
R. S. Crandall
Affiliation:
National Renewable Energy Laboratory, Golden, CO 80401
D. L. Williamson
Affiliation:
Physics Department, Colorado School of Mines, Golden, CO 80401
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Abstract

The optical and electronic properties of a series of microcrystalline silicon (μ-Si) films, deposited by the hot wire (HW) technique, are reported. Preliminary results suggest, using moderate H2 /SiH4 dilution ratios and substrate temperatures (320°C), high filament temperatures, and no H gas purifier, that the subgap absorption for these films, measured using the constant photocurrent (CPM) method, can be as low as that obtained for films deposited by the very high frequency glow discharge (VHF-GD) technique. The film dark conductivities of the HW samples, ranging as low as 2.0 × 10−8 (ohm cm)−1, lend further credance to these low defect values. At the same time, the optical absorption in the region > 1.6 eV is higher than that previously observed for the VHF-GD deposited samples. The present results, discussed in the context of the film microcrystalline fraction, suggest that there is no unique, good quality, low defect density μ-Si material, and that different deposition techniques can be used to successfully deposit device quality gc-Si. We also present optical and structural data for films deposited at lower substrate temperatures and higher deposition rates, and suggest combinations of deposition parameters to be used that may further improve the electronic properties of these films.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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References

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