The role of electric field-induced strain in the degradation mechanism of AlGaN/GaN high-electron-mobility transistors

摘要

The effect of strain induced by electric field in AlGaN/GaN high-electron-mobility transistors is investigated by theoretical calculations based on the minimization of the electric enthalpy functional. Results of the proposed model show that the converse piezoelectric effect increases (decreases) the stored elastic energy at positive gate voltage under biaxial tensile (compressive) strain, whereas it decreases (increases) at negative gate voltage. Hence, strain relaxation of piezoelectric origin is only expected in the on-state operation. In contrast, the degradation in the off-state operation could be identified with the effect of the electrostatic force generated by the increase in the stored electrostatic energy.