Simulation of AlGaN/GaN high-electron-mobility transistor gauge factor based on two-dimensional electron gas density and electron mobility

The gauge factor of AlGaN/GaN high-electron-mobility transistor was determined theoretically, considering the effect of stress on the two-dimensional electron gas (2DEG) sheet carrier density and electron mobility. Differences in the spontaneous and piezoelectric polarization between the AlGaN and GaN layers, with and without external mechanical stress, were investigated to calculate the stress-altered 2DEG density. Strain was incorporated into a sp(3)d(5)-sp(3) empirical tight-binding model to obtain the change in electron effective masses under biaxial and uniaxial stress. The simulated longitudinal gauge factor (-7.9 + 5.2) is consistent with experimental results (-2.4 + 0.5) obtained from measurements eliminating parasitic charge trapping effects through continuous subbandgap optical excitation. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3500465]