Gate Leakage and Breakdown Characteristics of AlGaN/GaN High-Electron-Mobility Transistors with Fe Delta-Doped Buffer

Meilan Hao

Abstract: This paper investigates the gate leakage mechanisms and off-state breakdown characteristics of Al0.23Ga0.77N/GaN High-Electron-Mobility transistors (HEMTs) with Fe delta-doped buffer on Al2O3. An insertion of an Fe doping layer was done at approximately ∼200 nm. Based on temperature-dependent current–voltage (I–V –T ) characteristics in the 100–300 K range, it was found that the trap-assisted Poole–Frenkel (PF) emission contributes to the gate leakage current in the lower reverse bias range (even below room temperature) and the emission barrier height of the interface traps extracted from the experimental results was around 17.93 meV∼97.122 meV. While near and above the threshold voltage, the conduction behavior is dominated by Fowler–Nordheim (FN) tunneling. Three-terminal off-state breakdown measurement indicated that it was the gate leakage which induced the HEMTs breakdown.