Self-aligned inversion-channel In 0.75 Ga 0.25 As MOSFETs using MBE-Al 2 O 3 /Ga 2 O 3 (Gd 2 O 3 ) and ALD-Al 2 O 3 as gate dielectrics

High-performance self-aligned inversion-channel In 0.75 Ga 0.25 As n-MOSFETs using in-situ ultra-high-vacuum (UHV) deposited Al 2 O 3 /Ga 2 O 3 (Gd 2 O 3 ) and ex-situ atomic-layer-deposited (ALD) Al 2 O 3 as gate dielectrics have been fabricated. Both devices exhibit excellent DC characteristics, including high drain currents and transconductances. A 1.2µm-gate-length In 0.75 Ga 0.25 As MOSFET using Al 2 O 3 (2nm-thick)/GGO(13nm-thick) dual-layer gate dielectric demonstrated a maximum drain current of 970 µA/µm, a peak transconductance of 410 µS/µm, and a peak mobility of 1560 cm 2 /V·s. A maximum drain current of 194 µA/µm and a peak transconductance of 126 µS/µm were exhibited by a 2µm-gate-length In 0.75 Ga 0.25 As MOSFET using ALD-Al 2 O 3 (6nm-thick).