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.