Low power AlGaN/GaN MEMS pressure sensor for high vacuum application

A micro-scale pressure sensor based on suspended AlGaN/GaN heterostructure is reported with non-linear sensitivity. By sealing the cavity, vacuum sensing at various temperatures was demonstrated. To validate the proposed concept of the AlGaN/GaN vacuum sensor, a 700 mu m diameter circular membrane was electrically characterized under applied static and dynamic pressures at various temperatures ranging from 25 degrees C to 100 degrees C. The current change of the AlGaN/GaN heterostructure increased as the vacuum and temperature increases due to the increase of 2DEG density by tensile strain. The dynamic current change from 96 kPa down to 10 Pa of AlGaN/GaN heterostructure pressure sensor was 18.75 % at 100 degrees C. The maximum sensitivity reached 22.8 %/kPa with a power consumption of 1.8 mu W. These results suggest that suspended AlGaN/GaN heterostructures are promising for high vacuum and high-temperature sensing applications. (C) 2020 Published by Elsevier B.V.