A Novel AlGaN/GaN-Based Schottky Barrier Diode With Partial P-GaN Cap Layer and Semicircular T-Anode for Temperature Sensors

This article presents a temperature sensor based on a partial p-GaN cap layer and a semicircular T-anode AlGaN/gallium nitride (GaN) Schottky barrier diode (PCT-SBD). The PCT-SBD uses a p-GaN layer and a semicircular T-anode to enlarge and adjust the position of the subthreshold region. This structure enabled better integration with AlGaN/GaN high-electron-mobility transistors (HEMTs) and improved the measurement accuracy of heterojunction temperature. The PCT-SBD temperature sensor exhibited great temperature sensitivity, reaching a maximum of 2.54 mV/K under 2.04 A/cm2 in the subthreshold region, which is approximately twice the temperature sensitivity of a regular GaN Schottky barrier diode (SBD) temperature sensor. Moreover, the device maintained good linearity, low turn-on voltage, and low reverse leakage current. The AlGaN/GaN PCT-SBD shows good potential in integrating with GaN-based power devices for temperature sensor applications.