Effect of annealing on the electrical and structural properties of rf-sputtered TaSi2 Schottky contacts to GaAs

TaSi2/GaAs Schottky contacts were fabricated, capped with SiO2, and annealed in flowing N2 at temperatures ranging from 400 to 900 °C. The electrical characteristics of the contacts were investigated through the use of current-voltage (I-V) and capacitance-voltage (C-V) techniques. The structure of the TaSi2/GaAs interface was studied by Auger electron spectroscopy. After annealing at temperatures up to 600 °C the electrical characteristics of the contacts improved. Degradation of the electrical characteristics was observed after annealing at temperatures above 600 °C. Some correlation was observed between the electrical characteristics and the structure of the GaAs/TaSi2 interface. The degradation is believed to be related to increased amounts of carbon and oxygen at the interface and an increased amount of oxygen in the TaSi2 film.