Low-power AlGaN/GaN pressure sensors for harsh environmental conditions with high sensitivity

Abstract

This study focuses on developing low-power, highly sensitive AlGaN/GaN pressure sensors for harsh environmental conditions, utilizing Au-free fabrication techniques to enable the integration of a readout-circuit on the same chip. For this purpose, a variation of membrane and device design is fabricated in Wheatstone bridge configuration and compared in terms of sensitivity, linearity and hysteresis performance at different pressure levels up to 1060 kPa and temperature conditions between 0°C and 100°C. The HEMT topology with a bossed membrane is identified as the most effective, offering superior sensitivity, linearity, and minimal hysteresis. The study highlights the novelty of using gated devices in a Wheatstone bridge configuration together with bossed, ring-shaped membranes for sensitivity scaling. The HEMT sensor with a 3 mm diameter ring-shaped membrane shows a peak sensitivity of 336.3 μVkPa, surpassing previously published results. Additionally, the sensors maintain a low energy consumption of approximately 8.33 mW.

Keywords

• Pressure sensor
• Strain sensing
• MEMS
• Harsh environment
• AlGaN/GaN HEMT
• High Electron Mobility Transistor