Normally Off GaN MOSFET Based on AlGaN/GaN Heterostructure With Extremely High 2DEG Density Grown on Silicon Substrate

A normally off GaN MOSFET was proposed by utilizing an extremely high 2-D electron-gas density (> 10¹⁴ / cm²) at an AlGaN/GaN heterostructure as source and drain, which can be obtained by controlling the tensile stress accompanied with the growth of GaN on silicon substrate. The fabricated MOSFET with an Al₂O₃ gate insulator exhibited excellent device performance, such as a threshold voltage of 2 V, drain current of 353 mA/mm, extrinsic transconductance of 98 mS/mm, and field-effect mobility of 225 cm²/V??s.