In-GaAs Schottky Barriers

Abstract

Schottky barriers have been made by evaporation of indium at a pressure of 1 × 10⁻⁶ torr onto chemically prepared n-GaAs. Ohmic contacts to the samples have been made by alloying In-Au composition (90:10 by wt) at a temperature of 550°C for 30 sec. Barrier height has been determined by using (i) C-V method, (ii) photoelectric method, and (iii) forward I-V characteristics. Barrier heights obtained by all the methods are in reasonably good agreement. Photoelectric method has also been used to determine the image force dielectric constant. But agreement in theory and experiment is not satisfactory. I-V characteristics showed that the barriers are true Schottky barriers with values of n very close to unity. n is found to vary with temperature as well as with diode area.