ULTRA-SUBMICROMETER-GATE ALGAAS/GAAS HEMTS

Ultra-submicrometer-gate AlGaAs/GaAs high-electron-mobility transistors (HEMT’s) with gate lengths ranging from 25 to 85 nm were fabricated, using electron-beam lithographic techniques on epitaxial wafers grown by molecular beam epitaxy. These devices show that velocity overshoot and short-gate geometry effects play an important role for gate lengths less than 100 nm. The maximum intrinsic transconductance is 215 mS/mm, and the effective saturated electron velocity reaches 3 × 107 cm/s for a 30-nm HEMT. © 1990 IEEE