Skip to main content Accessibility help
×
Home

Hydrogenated Amorphous Silicon Grown by Hot-Wire CVD at Deposition Rates up to 1 µm/minute

  • Brent P. Nelson (a1), Yueqin Xu (a1), A. Harv Mahan (a1), D.L. Williamson (a1) and R.S. Crandal (a2)...

Abstract

We grow hydrogenated amorphous-silicon (a-Si:H) by the hot-wire chemical vapor deposition (HWCVD) technique. In our standard tube-reactor we use a single filament, centered 5 cm below the substrate and obtain deposition rates up to 20 Å/s. However, by adding a second filament, and decreasing the filament-to-substrate distance, we are able to grow a-Si:H at deposition rates exceeding 167 Å/s (1 µm/min). We find the deposition rate increases with increasing deposition pressure, silane flow rate, and filament current and decreasing filament-tosubstrate distance. There are significant interactions among these parameters that require optimization to grow films of optimal quality for a desired deposition rate. Using our best conditions, we are able to maintain an AM1.5 photoconductivity-to-dark-conductivity ratio of 105 at deposition rates up to 130 Å/s, beyond which the conductivity ratio decreases. Other electronic properties decrease more rapidly with increasing deposition rate, including the ambipolar diffusion length, Urbach energy, and the as-grown defect density. Measurements of void density by small-angle X-ray scattering (SAXS) reveal an increase by well over an order of magnitude when going from one to two filaments. However, both Raman and X-ray diffraction (XRD) measurements show no change in film structure with increasing deposition rates up to 144 Å/s, and atomic force microscopy (AFM) reveals little change in topology.

Copyright

References

Hide All
1. Branz, H.M., Collins, R.W., Okamoto, H., Guha, S., and Schropp, R. editors, Part II: High-Deposition Rate, Mater. Res. Soc. Proc. 557, San Francisco, CA, 1999 pp 105144.
2. Carlson, D.E. and Wronski, C.R., Appl. Phys. Lett. 28, 671 (1976).
3. Mahan, A.H. and Vanecek, M., Amer. Inst. of Phy. Conf. Proc. 234, 195 (1991).
4. Nelson, B.P., Xu, Y., Williamson, D.L., Roedern, B. von, Mason, A., Heck, S., Mahan, A.H., Schmitt, S.E., Gallagher, A.C., Webb, J., and Reedy, R., Mater. Res. Soc. Proc. 507, San Francisco, CA, 1998 pp 447452.
5. Nelson, B.P., Xu, Y., Webb, J.D., Mason, A., Reedy, R.C., Gedivals, L.M., and Lanford, W.A., Jour. Non-Cryst. Solids, 5204, 6755, (Elsevier, 4 January 2000).
6. Nelson, B.P., Iwaniczko, E., Schropp, R.E.I., Mahan, A.H., Molenbroek, E.C., Salamon, S., and Crandall, R.S., in Proceedings of the 12th European Photovoltaic Solar Energy Conference (H.S. Stephens and Associates, Bedford UK, 1994), pp. 679682.
7. Wang, Q., Iwaniczko, E., Xu, Y., Nelson, B.P., and Mahan, A.H., Mater. Res. Soc. Proc. 557, San Francisco, CA, 1999 pp 163168.
8. Nelson, B.P., Crandall, R.S., Iwaniczko, E., Mahan, A.H., Wang, Q., Xu, Y., and Gao, W., Mater. Res. Soc. Proc. 557, San Francisco, CA, 1999 pp 97102.
9. Mahan, A.H., Mason, A., Nelson, B.P., and Gallagher, A.C., , Gao, Mater. Res. Soc. Proc. (this volume), San Francisco, CA, 2000.

Hydrogenated Amorphous Silicon Grown by Hot-Wire CVD at Deposition Rates up to 1 µm/minute

  • Brent P. Nelson (a1), Yueqin Xu (a1), A. Harv Mahan (a1), D.L. Williamson (a1) and R.S. Crandal (a2)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed