DC and Pulse I-V Characteristics of Strain-Engineered AlGaInN/GaN HEMTs fabricated on Single-Crystal AlN Substrate

A high-electron-mobility transistor (HEMT) structure consisting of a strain-engineered quaternary AlGaInN barrier layer on an unintentionally doped (UID) GaN channel layer is grown on a single-crystal (SC) AlN substrate by metal-organic chemical vapor deposition and subjected to the device fabrication and characterization. It is showed in DC static measurement results that the fabricated HEMTs exhibit good current-voltage (I-V) characteristics without large negative resistance even at high-current operations. Pulse I-V measurements results indicate that the fabricated devices show a low-drain-current collapse as unpassivated GaN HEMTs and that it is further improved by applying an Al2O3 surface passivation. The present results signify promising prospects of AlGaInN/GaN HEMTs on SC-AlN toward future high-power radio-frequency (RF) applications.