Si₃N₄ double passivation methods for optimizing the DC properties in a gamma-gate AlGaN/GaN HEMT using Plasma Enhanced Chemical Vapor Deposition

Double passivation layers, Si₃N₄ on Si ₃N₄ (Si₃N₄ / Si₃N 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 SiO₂ on SiO₂ (SiO₂ / SiO₂). Both samples were tested under the same conditions: V_ds = 0 to 15 V and V_gs = 1 to -5 V. The Si₃N₄ / Si ₃N₄ 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) -4.5 V, which increases up to 18% and 5% than those of SiO₂/SiO ₂ double passivation.