Hostname: page-component-669899f699-qzcqf Total loading time: 0 Render date: 2025-04-25T03:08:04.705Z Has data issue: false hasContentIssue false
  • English
  • Français

Amorphous Thin Film Diffusion Barriers on GaAs and InP

Published online by Cambridge University Press:  15 February 2011

W. T. Anderson JR. ,
A. Christou  and
J. E. Davey
W. T. Anderson JR.
Affiliation:
Naval Research Laboratory, Washington, DC 20375, (U.S.A.)
A. Christou
Affiliation:
Naval Research Laboratory, Washington, DC 20375, (U.S.A.)
J. E. Davey
Affiliation:
Naval Research Laboratory, Washington, DC 20375, (U.S.A.)
Get access

Abstract

Thin film amorphous W-Si and TiW-Si diffusion barriers have been studied on GaAs and InP surfaces for the purpose of establishing their reliability for ohmic contacts and Schottky barriers, particularly under high temperature stress. The amorphous films were formed by a new method in which alternate layers of tungsten or TiW and silicon were sputter deposited to a total thickness of about 1300 Å and subsequently annealed near the glass transition temperature Tg(≈ 500 °C). Electron channeling and reflection electron diffraction were used to determine the amorphous nature of the films as deposited and after 4 h anneals near Tg. The as-deposited films had interfacial amorphous regions with compositions determined by interfacial reactions during the sputtering process. As-deposited W-Si films showed a weak channeling pattern which came from the unreacted polycrystalline tungsten layers. From Auger electron spectroscopy (AES) sputter profiles, it was concluded that the amorphous regions were at the W-Si interfaces which had the required tungsten-to-silicon composition ratio. After annealing at 500 °C for 4 h, the films were completely amorphous with no marked evidence of crystallization, indicating interfacial reactions extended completely into the tungsten layers. High magnification scanning electron microscopy (by a factor of 20 000) examination of the films after annealing revealed smooth and continuous surfaces with no evidence of grain boundaries. Diffusion along grain boundaries between gold and GaAs or InP in these amorphous thin films was thus almost completely eliminated. Interdiffusion of gold in layered structures (e.g. Au/(W–Si)/GaAs) was studied by AES sputter profiling techniques. No interdiffusion of gold or GaAs was observed after 16 h anneals at 400 °C. With Au/(W-Si)/InP structures, no interdiffusion was observed after 8 h anneals at 450 °C. These results are significant improvements over those for previous polycrystalline diffusion barriers (e.g. TiPt) which degrade after 1 h at 350 °C. Based on the AES sputter profiles, the diffusion coefficients in W-Si amorphous thin films were found to be less than 3 × 10−18 cm2 s−1 at 400 °C for gold, gallium and arsenic and less than 6 × 1018 cm2 s−1 at 450 °C for gold, indium and phosphorus.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 18: Symposium C – Interfaces and Contacts , 1982 , 57
Copyright
Copyright © Materials Research Society 1982

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.)

Article purchase

Temporarily unavailable

References

REFERENCES

1 White, P. M., Hewitt, B. L. and Turner, J. S., Reliability investigation of GaAS power FETs with aluminum gate, Eur. Microwave Conf., Paris, 1978.Google Scholar
2 Irvin, J. C. and Loya, A., Bell Syst. Tech. J., 57 (8) (1978) 2823–2846.Google Scholar
3 Drukir, I. and Silcox, J. F., Proc. IRPS, San Francisco, CA, 1979.Google Scholar
4 Cohen, E. D. and Macpherson, A. C., Proc. IRPS, San Francisco, CA, 1979, pp. 156–160.Google Scholar
5 Christou, A., J. Appl. Phys., 47 (12) (1976) 5464–5468.Google Scholar
6 Kim, H. B., Sweeney, G. G. and Heng, T., Res. Lab. Rep. 74-1F6-IMPA TT-PI, 1974 (Westinghouse Corporation).Google Scholar
7 Christou, A., Scanning Electron Microscopy 1979, Vol. I, SEM Inc., AMF O'Hare, 1979.Google Scholar
8 Calviello, J. A. and Wallace, J. L., IEEE Trans. Electron Devices, 24 (1977) 698–704.Google Scholar
9 Sleger, K. and Christou, A., Solid-State Electron., 21 (1978) 677–684.Google Scholar
10 Chen, H. S., Kimerling, L. C., Poate, T. M. and Brown, W. L., Appl. Phys. Lett., 32 (1978) 461.Google Scholar
11 Rosenblum, M. P., Spaepen, F. and Turnbull, D., Appl. Phys. Lett., 37 (1980) 184.Google Scholar
12 Naka, M., Hashimoto, K. and Masumoto, T., J. Non-Cryst. Solids, 28 (1978) 403.Google Scholar
13 Wiley, D., Perepezko, H. and Nordman, J. E., Rep. SAND80-71 67, 1980 (Sandia Laboratories, Albuquerque, NM).Google Scholar
14 Guo, K. J. and Wiley, J. D., Amorphous metal diffusion barriers, Proc. 2nd Conf. on High Temperature Electronics and Instrumentation, Houston, TX, December 7-8, 1981.Google Scholar
15 Christou, A., Anderson, W. T. Jr., Bark, M. L. and Davey, J. E., 20th Annu. Proc. Reliability Physics, 1982, IEEE, New York, 1982, pp. 188–193.Google Scholar
16 Portnoy, W., Texas Technical University, personal communication.Google Scholar
17 Papanicolaou, N. A., Anderson, W. T. Jr., and Christou, A., Small signal MESFET with sputtered amorphous metal gate defined by lift-off, Gallium Arsenide and Related Compounds 1982, in Inst. Phvs. Conf. Ser., to be published.Google Scholar