Frequency dependence of capacitance-voltage characteristics caused by D X centers in Si-doped AlGaAs

Abstract

Capacitance of Schottky barrier diodes formed on Si-doped AlxGa1−xAs (x>0.25) decreases as the measuring frequency increases from 1 kHz to 1 MHz at room temperature. As a result of this frequency dependence, apparent donor concentrations become smaller than the true values at a measuring frequency of 1 MHz, which is widely used for derivation of donor concentrations. This frequency dependence is caused because charging and discharging at DX centers does not follow the 1-MHz measuring frequency even at room temperature. This result is important for characterizing n-AlGaAs and for its applications to electronic and optical devices.