Si3N4 Double Passivation Methods for Optimizing the DC Properties in a Gamma-Gate AlGaN/GaN HEMT Using Plasma Enhanced Chemical Vapor Deposition

Abstract

Double passivation layers, Si3N4 on Si3N4 (Si3N4 / Si3N4), have been implemented onto the top and bottom surface passivation film layers for a gamma-gate AlGaN/GaN HEMT using Plasma Enhanced Chemical Vapor Deposition (PECVD). The effects of the reduced current collapse electro characteristics were then compared to devices using double passivation as SiO2 on SiO2 (SiO2 / SiO2). Both samples were tested under the same conditions: Vds = 0 to 15 V and Vgs = 1 to -5 V. The Si3N4 / Si3N4 passivation results show a maximum saturation current density (Ids max) of 761 mA/mm, a peak extrinsic trans conductance (gm max) of 200 mS/mm, and threshold voltages of (Vth) -4.5 V, which increases up to 18% and 5% than those of SiO2/SiO2 double passivation.