AlGaAs defect characterization in high electron mobility transistors by thermally stimulated drain conductance

A method based on monitoring the thermally stimulated drain conductance (TSDC) under trap filling and emptying bias-temperature sequences is developed for directly characterizing high defect density AlGaAs layers in high electron mobility transistors (HEMT´s). The rate equation for trapped electron emission is solved for the conditions pertinent to the TSDC method. Measured results on HEMT´s are in excellent agreement with this solution and compare favorably with values reported by others. TSDC is as convenient to implement but more applicable than deep-level transient spectroscopy (DLTS) for the high concentration of AlGaAs defects normally encountered in HEMT´s.