Study of a High-Sensitivity Recessed-Anode GaN MIS Diode for Temperature Sensing

In this paper, a temperature sensor with a partial P-GaN cap layer and a semicircular recessed anode AlGaN/GaN MIS diode is presented. The sensor utilizes the depletion effect of the P-GaN layer and the passivation effect of the insulating dielectric layer to reduce the diode’s forward current. Additionally, the recessed anode structure helps mitigate longitudinal dislocation defects within the epitaxial layers. As a result, the sensor exhibits excellent temperature sensitivity across a wide temperature range from 25 °C to 200 °C. The proposed sensor achieves a maximum sensitivity of 4.77 mV/K at a current density of 0.00013 A/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, which is approximately 3.2 times higher than that of conventional GaN SBD temperature sensors. The device also maintains a low reverse leakage current due to the insulating dielectric layer.