Influence of passivation induced stress on the performance of AlGaN/GaN HEMTs

This paper reports on properties of intentionally undoped AlGaN/GaN/sapphire-based high electron mobility transistors (HEMTs) before and after passivation with SiO2 and Si3N4. Our results indicate that the DC performance of the AlGaN/GaN HEMTs improved significantly as the stress in the passivation layer increased from compressive to tensile. It corresponded to changes in the sheet carrier concentration. Unlike the DC properties, RF properties of the HEMTs were less sensitive to the stress. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)