Effect of surface passivation of AlGaN/GaN heterostructure field-effect transistor

The effect of SiN passivation of the surface of AlGaN/GaN transistors is reported. Current deep level transient spectroscopy (DLTS) measurements were performed on the device before and after the passivation by a SiN film. The DLTS spectra from these measurements showed the existence of the same electron trap on the surface of the device. The DLTS spectrum obtained from the measurement of the passivated device showed a significantly lower peak for this trap. The discrepancy in the DLTS peak amplitude is explained by the effect of the passivation on the surface traps and underlines the surface nature of the major defect noticed in the device.