Hostname: page-component-8448b6f56d-tj2md Total loading time: 0 Render date: 2024-04-23T19:42:57.451Z Has data issue: false hasContentIssue false
  • English
  • Français

Hydrogen Bonding, and Microvoids in a-Si:H: a Proton NMR Study

Published online by Cambridge University Press:  25 February 2011

M. Zheng ,
E.J. VanderHeiden ,
P.C. Taylor ,
R. Shinar ,
S. Mitra  and
J. Shinar
M. Zheng
Affiliation:
Department of Physics, University of Utah, Salt Lake City, UT 84112
E.J. VanderHeiden
Affiliation:
Department of Physics, University of Utah, Salt Lake City, UT 84112
P.C. Taylor
Affiliation:
Department of Physics, University of Utah, Salt Lake City, UT 84112
R. Shinar
Affiliation:
Microelectronics Research Center, Iowa State University, Ames, IA 50011
S. Mitra
Affiliation:
Ames Laboratory-USDOE and Physics Department, Iowa State University, Ames, IA 50011
J. Shinar
Affiliation:
Ames Laboratory-USDOE and Physics Department, Iowa State University, Ames, IA 50011
Get access

Abstract

The cw proton NMR spectra, spin lattice relaxation times Tx and free induction decay times T*2 were measured in various a-Si:H films deposited by rf-sputtering. All spectra exhibited broad and narrow components, of T*2 ∼ 20 and 45 μsec, respectively. In samples deposited at high rf power, the ratio of the integrated intensities of the broad and narrow lines was ∼ 1.5. These samples, which apparently contain mainly bulk monohydride bonds and a low volume fraction of microvoids, exhibit long-range H motion. In a sample deposited at low rf power, this ratio was ∼ 3. These samples, which contain significant dihydride and microvoid content, show a dramatic suppression of the long-range H motion. The T1 of both types of samples exhibits a clear minimum at ∼ 30 K, indicative of relaxation by H2 trapped in microvoids. The absolute values of T1, however, are smaller in the sample deposited at low rf power (0.1 sec at the minimum as opposed to 0.3 to 1.0 sec at the minimum), apparently due to a larger ratio of molecular hydrogen to bonded hydrogen. After annealing for 24 hours at 294°C, the ratio of broad-to-narrow components increases to > 10 in all samples, and the magnitudes of the T1 minima increase to about 1 sec in all samples.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 192: Symposium O – Amorphous Silicon Technology - 1990 , 1990 , 657
Copyright
Copyright © Materials Research Society 1990

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Reimer, J. A., Vaughan, R.W. and Knights, J. C., Phys. Rev. B 23, 2567 (1981); B 24 3360 (1981).Google Scholar
Carlos, W. E. and Taylor, P.C., Phys. Rev. B 25, 1435 (1982).Google Scholar
Taylor, P. C. in Semiconductors and Semimetals, Vol. 21C, Pankove, J.I., ed. (Academic, N.Y., 1984), p. 99.Google Scholar
Baum, J., Gleason, K.K., Pines, A., Garroway, A.N. and Reimer, J. A., Phys. Rev. Lett. 56, 1377 (1986).Google Scholar
5. Carlos, W. E. and Taylor, P. C., Phy. Rev. B 26, 3605 (1982)Google Scholar
6. Shinar, J., Shinar, R., Mitra, S. and Kim, J.-Y., Phys. Rev. Lett. 62, 2001 (1989).Google Scholar
7. VanderHeiden, E. J., Ohslen, W.D. and Taylor, P.C., J. Non-Cryst. Solids 66, 115 (1984).Google Scholar
8. Conradi, M.S. and Norberg, R.E., Phys. Rev. B 24 2285 (1981).Google Scholar