An Etch-Stop Barrier Structure for GaN High-Electron-Mobility Transistors

We present an etch-stop barrier structure for GaN high-electron-mobility transistors. With this new etch-stop structure, gate recess can be precisely controlled while maintaining a low surface defect density. Normally off GaN metal-insulator-semiconductor FETs fabricated using the new technology demonstrated a record effective channel mobility of 1131 cm ² ·V ^-1 ·s ^-1 with a subthreshold slope of 62 mV/decade. Due to the low interface density of states, these devices have very low hysteresis and negligible frequency dispersion in the capacitance-voltage ( C - V ) measurements.