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Metallurgical Reactions in Au/Ge/Au Contact to Gallium Arsenide

Published online by Cambridge University Press:  26 February 2011

Taeil Kim ,
DDL Chung  and
S Mahajan
Taeil Kim
Affiliation:
Department of Metallurgical Engineering and Materials Science, Carnegie-Mellon University, Pittsburgh, PA 15213
DDL Chung
Affiliation:
Department of Metallurgical Engineering and Materials Science, Carnegie-Mellon University, Pittsburgh, PA 15213
S Mahajan
Affiliation:
Department of Metallurgical Engineering and Materials Science, Carnegie-Mellon University, Pittsburgh, PA 15213
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Abstract

Transmission electron microscopy (TEM), was used to study the interfacial structure resulting from the alloying reaction of a Au/Ge/Au film on (100) GaAs. The metallurgical reaction at 400°C results in the previously unknown hexagonal Au3Ga phase. The crystal structure of the AuoGa phase is proposed based on the observed diffraction patterns and the lattice image The well-known fcchcp coherent jnterface is observed between Au and Au3Ga such that (111)Au // (0001)Au3Ga and [110]. // [1120]Au2Ga. In addition to Au3Ga, other Au-Ga compounds (Au7Ga2, Au2Ge), a Au-Ge metastabil phase, and a Au-Ge-As ternary phase were observed after annealing. After annealing above 400°C, epitaxially regrown GaAs crystallites on the underlying GaAs substrate were revealed by cross-section TEM. The current flows through these Ge-doped regrown GaAs regions and the contact becomes ohmic The size and density of the regrown GaAs crystallite increase with increasing annealing temperature between 400 and 500°C; this explains the decreasing tendency of contact resistance with increasing annealing temperature.

Type
Articles
Information
MRS Online Proceedings Library (OPL) , Volume 77: Symposium D – Interfaces, Superlattices, and Thin Films , 1986 , 369
Copyright
Copyright © Materials Research Society 1987

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References

REFERENCES

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