Low-temperature and pressure response of InAlN/GaN ring-shaped high electron mobility transistors

A ring-shaped InAlN/GaN high electron mobility transistor (HEMT) is leveraged as the sensing element of a micro-pressure sensor. The microfabrication process, which uses an InAlN/GaN-on-Si substrate, enables monolithic integration with other electronic devices, as well as operation within harsh environments. The micropressure sensor was characterized from 0 to 14 psig at room temperature (RT) and -3°C. Current-voltage (I-V) measurements under applied pressures exhibited a decrease in percent change in current (sensitivity) at -3°C, compared to RT. At RT and -3°C (VGS = - 4 V), the maximum current sensitivity is 0.61%/psig (at VDS = 3.4 V) and 0.39%/psig (at VDS = 4 V), respectively. These results suggest that the InAlN/GaN platform can extend sensing capabilities to cold harsh environments (e.g., space and Arctic exploration).