Comparison of Surface Passivation Films for Reduction of Current Collapse in AlGaN/GaN High Electron Mobility Transistors

Abstract
Three different passivation layers (SiNX,(SiNX, MgO, and Sc2O3)Sc2O3) were examined for their effectiveness in mitigating surface-state-induced current collapse in AlGaN/GaN high electron mobility transistors (HEMTs). The plasma-enhanced chemical vapor deposited SiNXSiNX produced ∼70-75% recovery of the drain-source current, independent of whether SIH4/NH3SIH4/NH3 or SiD4/ND3SiD4/ND3 plasma chemistries were employed. Both the Sc2O3Sc2O3 and MgO produced essentially complete recovery of the current in GaN-cap HEMT structures and ∼80-90% recovery in AlGaN-cap structures. The Sc2O3Sc2O3 had superior long-term stability, with no change in HEMT behavior over 5 months aging. © 2002 The Electrochemical Society. All rights reserved.