Investigation of III-Nitride MEMS Pressure Sensor for High-Temperature Applications

Area of Science:

• Materials Science
• Electrical Engineering
• Mechanical Engineering

Background:

• AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) possess wide bandgap properties suitable for high-temperature applications.
• Micro-Electro-Mechanical Systems (MEMS) pressure sensors require robust designs for extreme operational conditions.

Purpose of the Study:

• To investigate the high-temperature performance of AlGaN/GaN HFET-based MEMS pressure sensors.
• To evaluate sensor stability, sensitivity, and response time at elevated temperatures.

Main Methods:

• Experimental characterization of sensor resistance change under varying pressure at room temperature and up to 250 °C.
• COMSOL-based Finite Element (FE) simulations coupled with a theoretical model to predict sensor response.
• Gate-bias dependent analysis to assess sensitivity tunability.

Main Results:

• A significant change in drain-source resistance (ΔR_DS/R_DS(0)) of 0.32% at room temperature and 0.65% at 250 °C was observed.
• FE simulations closely matched experimental results, with a theoretical ΔR_DS/R_DS(0) of 0.45% at room temperature.
• Enhanced sensitivity was achieved with negative gate voltages, and stable operation was confirmed up to 300 °C with a response time <10 ms.

Conclusions:

• AlGaN/GaN HFET-based MEMS pressure sensors demonstrate stable and reliable performance at high temperatures.
• The sensor's tunable sensitivity and rapid response time make it suitable for harsh, high-temperature environments.
• The combination of experimental and simulation methods validates the sensor's design and predicted performance.