Hostname: page-component-7c8c6479df-xxrs7 Total loading time: 0 Render date: 2024-03-28T13:33:14.948Z Has data issue: false hasContentIssue false

The Effects of Thermal Processing on Interfacial Microstructure for Thin Multilayered Metal Ohmic Contacts to p+-AlGaAs

Published online by Cambridge University Press:  15 February 2011

M.W. Cole
Affiliation:
Army Research Laboratory, Ft. Monmouth, NJ 07703
W.Y. Han
Affiliation:
Army Research Laboratory, Ft. Monmouth, NJ 07703
K.A. Jones
Affiliation:
Army Research Laboratory, Ft. Monmouth, NJ 07703
Get access

Abstract

Interfacial microstructure and phase composition of PtTiGePd ohmic contacts to heavily C doped AlGaAs were investigated as a function of annealing temperature. Results of the material analyses were used to explain the specific contact resistances measured for each thermal treatment. Evidence of interdiffusion and compound formation between AIGaAs and Pd was visible in a Ga rich Pd-Ga-As reaction zone prior to heat treatment. This phase is critical for the formation of Ga vacancies, which upon heating are occupied by in-diffusing Ge. As the annealing temperature was elevated, from 530 - 600°C, As began to out-diffuse. This As out-diffusion, which is critical to the formation of good p-type ohmic contacts, contributed to the creation and development of the two phase TiAs/Pd12Ga2Ge5 interfacial region overlying the AlGaAs substrate. In response to the enhanced As out-diffusion at 600°C, the interfacial region became laterally continuous, compositionally uniform, and the specific contact resistance achieved its minimum value. Athigher annealing temperatures, ∼650°C, the electrical measurements degraded in response to intensive chemical diffusion and development of a broad, non-uniform multi-phased interfacial region.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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

1. Han, W.Y., Cole, M.W., Casas, L.M., Jones, K.A., Wade, M., DeAnni, A., Lepore, A., Lu, Y. and Yang, L.W., to be published.Google Scholar
2. Cole, M.W., Han, W.Y., Casas, L.M., Eckart, D.W. and Jones, K.A., J. Vac. Sci. Technol. A 12(4), 1904 (1994).Google Scholar
3. Marshall, E.D., Zhang, B., Wang, L.C., Jiao, P.F., Chen, W.X., Sawada, T., Lau, S.S., Kavanagh, K.L. and Kuech, T.F., J. Appl. Phys. 62, 942 (1987).Google Scholar
4. Sands, T., Keramidas, V.G., Yu, K.M., Washburn, J. and Krishnan, K., J. Appl. Phys. 62, 2070 (1987).Google Scholar
5. Katz, A., Abernathy, C.R., Pearton, S.J., Weir, B.E., and Savin, W., J. Appl. Phys. 69(4), 2276 (1991).Google Scholar
6. Shih, Yih-Chang, Murakami, Masanore, Wilkie, E.L. and Callegari, A.C., J. Appl Phys 62, 582 (1987).Google Scholar