Dielectric studies of metal/n-GaN/metal Schottky contact in the radio frequency range

Abstract

Capacitance–voltage and capacitance–frequency characteristics of the metal/n-GaN/metal Schottky contacts with Au, Al and Ag electrodes were investigated as a function of the temperature and external electric field in the frequency range from 100 to 300 kHz. Forward capacitance–voltage measurements were carried out in the frequency range from 100 Hz to 20 MHz. The temperature capacitance coefficient and the electrical tunability were measured as a function of the external DC field for all contacts. The capacitance and dielectric loss measurements show relaxation peaks from 4 to 11 kHz for some electrodes, indicating that interfacial effects play an important role in the electrical properties of the GaN Schottky barrier contact. Low-frequency relaxation studies were conveniently used to probe interfacial characteristics of the contacts.