Sputter Etching Effects on GaAs Schottky Junctions

Abstract

The electrical properties of Schottky junctions with rf sputter etching, immediately before sputter deposition of metals, and their thermal recovery characteristics are described. Sputter etching not only results in removal of surface layers, but also in formation of a thin (∼100Å) damage layer, which decreases the Schottky junction effective barrier height. Thermal recovery characteristics strongly depend on sputter‐etching conditions, such as rf‐power and etching time. The activation energy for thermal recovery is continuously distributed, even in one sample. The results suggest that the damage is in lattice disorder and the degree of disorder depends on energy and/or dose of incident ions. The damage introduced during low power (50W) sputter‐etching is completely annihilated by thermal annealing at 350°C. The barrier height uniformity after annealing is improved by sputter etching at low power. It has been confirmed that sputter etching is a useful technique for surface treatment in the fabrication of Schottky junctions with uniform barrier height.