Si_3N_4 Double Passivation Methods for Optimizing the DC properties in a Gamma-Gate AlGaN/GaN HEMT using Plasma Enhanced Chemical Vapor Deposition

摘要

Double passivation layers, Si_3N_4 on Si_3N_4 (Si_3N_4/Si_3N_4), 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 SiO_2 on SiO_2 (SiO_2/SiO_2). Both samples were tested under the same conditions: V_(ds) = 0 to 15 V and V_(gs) = 1 to -5 V. The Si_3N_4/Si_3N_4 passivation results show a maximum saturation current density (I_(ds max)) of 761 mA/mm, a peak extrinsic trans conductance (g_(m max)) of 200 mS/mm, and threshold voltages of (V_(th))-4.5V, which increases up to 18% and 5% than those of SiO_2/SiO_2 double passivation.