Stable High Temperature Operation of p-GaN Gate HEMT With Etch-Stop Layer

High -temperature operation of the p-GaN gate high -electron -mobility transistor (HEMT) was investigated, specifically up to 500 degrees C. The p-GaN gate HEMT demonstrated stable behavior with normally -off operation, steep increase of drain current in the subthreshold region, and suppressed off -state current. By adding Al2O3 etch -stop layer, the device showed significant reduction in subthreshold swing when measured at 500 degrees C, effectively mitigating hysteresis in the transfer characteristics. Additionally, the lifetime of the gate stack with the etch -stop layer was estimated to be much longer than that of the stack without the etch -stop layer. Through the integration of the depletion -mode (D -mode) metal -insulator -semiconductor HEMT (MIS-HEMT) device with the p-GaN gate device, a direct -coupled field-effect transistor logic (DCFL) inverter was fabricated. This inverter showed stable logic operation up to 500 degrees C, featuring rail -to -rail operation and large gain. A long-term reliability test conducted at 500 degrees C for 100 hours revealed stabilized on -state and off -state values after about 50 hours of operation.