High-temperature annealing of the SiO2/GaAs system

Abstract

A neutron activation technique has been used to analyze the gallium content in SiO2 films deposited on n-type GaAs. Gallium was observed in the SiO2 films after annealing at temperatures between 730 and 940 °C. It is found that the surface of GaAs reacts with the H2O in the SiO2 films and/or ambient gas via pinholes at these high temperatures. The reaction is influenced by the partial pressure of water in the ambient gas.

Novel Techniques for the Fabricating and Characterization of GaAs MIS (Metal Insulator Semiconductor) Structures.

“…Otherwise, Auger analysis showed the other surface preparations to be approximately equivalent with each leaving a thin contamination layer of C, 0, and Cl. We found that the normal surface treatment which we employ prior to liquid phase epitaxial growth (#1 in Table 1) and the NH 4 OH treatment (#5 in Table 1) gave the most reproducible results for a number of individual devices measured over a large area wafer. Accordingly we employed these surface treatments prior to in-situ etching in future work.…”

“…Film uniformity in thickness and composition was excellent over the entire range of substrate temperature and deposition pressures tested, with variations of less than 5% over a 3-inch wafer. Si0 2 films were deposited in an Applied Materials chemical vapor deposition system using SiH 4 and 02 in a nitrogen carrier gas. The films typically exhibited an index of refraction between 1.45 and 1.47.…”