Location identify of EC-0.9 eV trap in AlGaN/GaN high electron mobility transistors

Abstract

This paper identifies the location of EC-0.9 eV trap caused by irradiation in AlGaN/GaN high electron mobility transistors (AlGaN/GaN-HEMTs). Helium ions at 40 keV and 400 keV were selected as the irradiation source. The 40 keV He ions only causes damage in the passivation and AlGaN layer, while the 400 keV He ions will cause damage mainly in GaN layer. The test results show that the threshold voltage of the device positive shift after 400 keV He ion irradiation. The carrier mobility and the Schottky barrier also show decreases. Deep level transient spectrum (DLTS) results show a defect with EC-0.9 eV in GaN layer after irradiation. While, the displacement damage in the passivation and AlGaN layer cause negative shift of the threshold voltage and the decrease of the carrier mobility. Combined with the DLTS and TCAD simulation, the location of defects with EC-0.9 eV caused by displacement damage is in the GaN layer.