Reaction at a platinum-gallium arsenide interface

• Published in: Surface science Vol. 104; no. 2; pp. 341 - 353
• Main Authors: Begley, D.L., Alexander, R.W., Bell, R.J., Goben, C.A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.1981
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(81)90064-9

The reaction at a Pt/n-GaAs interface as a result of annealing at 400°C was investigated. Both electron beam evaporated and electro-plated Pt films were studied. Optical reflection and transmission spectroscopy, secondary ion mass spectroscopy, X-ray diffractometry, scanning electron and ion microscopy, and X-ray energy spectroscopy were employed to examine the metal-semiconductor interface. An increase in the optical reflectivity was observed early in the annealing sequence. As has been observed by others, a complex layered structure formed at the interface, but the electron and ion micrographs revealed that gallium diffused rapidly through the platinum film at apparent imperfections in the Pt film. These imperfections were not visible in the micrographs prior to annealing and their nature has not been determined. These areas are believed to be primary sites for premature device failure. It appears that techniques such as SIMS which average over micron-sized or larger areas which indicate gallium diffusion to the Pt surface are correct, but may be misleading as to the mechanism.