Measurement of piezoresistance coefficient with different gate voltages of GaN HEMT micro-accelerometer

Through experiments and simulations, the piezoresistance coefficients of AlGaN/GaN HEMT under different gate voltages in the structure of micro-accelerometer are studied. The results show that piezoresistance coefficient at room temperature (RT) is equivalent to (2.47±0.04)×10-9 Pa^-1, which is higher than that of silicon. The Current-Voltage characteristics of HEMT at different gate voltages were measured and the piezoresisitance coefficients under different temperatures were calculated. The conclusion is drawn that the drain saturation current and piezoresistance coefficient of HEMT decreases with the increase of the temperature. It has relation with the concentration of 2DEG and polarization effect.