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

摘要

Three different passivation layers (SiN(x), MgO, and 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 SiN(x) produced (caret) 70 to 75 percent recovery of the drain-source current, independent of whether SIH4/NH3 or SiD4/ND3 plasma chemistries were employed. Both the Sc2O3 and MgO produced essentially complete recover of the current in GaN-cap HEMP structures and (caret) 80 to 90 percent recovery in AlGaN-cap structures. The Sc2O3 had superior long-term stability, with no change in HEMT behavior over 5 months of aging.