On-Chip Integrated High-Sensitivity Temperature Sensor Based on <i>p</i>-GaN/AlGaN/GaN Heterostructure
Jie Chang, Yulian Yin, Jiahong Du, Huan Wang, Haoran Li, Changhui Zhao, Hui Li, Cungang Hu, Wenping Cao, Xi Tang, Shu Yang
Abstract
An on-chip integrated temperature sensor based on a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula> -GaN/AlGaN/GaN heterostructure is demonstrated. The sensor consists of a two-dimensional-electron-gas (2DEG) resistor and a Schottky-metal/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${p}$ </tex-math></inline-formula> -GaN/AlGaN/GaN (PiN) diode, which are connected in series and fabricated on one heterostructure. The conduction current of the 2DEG resistor features a negative temperature-dependence, while that in the PiN diode features a positive dependence due to its bipolar-electron/hole-injection nature. When they are properly biased, the divided voltage between the two units is redistributed with elevated temperatures. At a supply voltage of 10 V, the sensor presents a maximum and recorded sensitivity of 19.7 mV/°C in a temperature range from 25 °C to 300 °C due to the opposing temperature dependence of the two units. The fabrication process and the heterostructure of the temperature sensor are fully compatible with high-electron-mobility transistors, enabling in situ temperature detection and protection with enhanced accuracy and sensitivity.