Abstract
TiN/Ga2O3(Gd2O3)[GGO]/GaAs and /In0.2Ga0.8As MOS diodes after rapid thermal annealing (RTA) to high temperatures of 750□C exhibit excellent electrical and structural performances: a low leakage current density of 10-8 - 10-9 A/cm2, well-behaved capacitance-voltage (C-V) characteristics giving a high dielectric constant of ~16 and a low interfacial density of state of ~(2~6)×1011 cm-2eV-1, and an atomically sharp smooth GGO/GaAs and /In0.2Ga0.8As interface. A self-aligned process for fabricating inversion n-channel metal-oxide-semiconductor field-effect-transistors (MOSFET’s) of strained In0.2Ga0.8As- or GaAs-channel using TiN as gate metal and Ga2O3(Gd2O3) as high k gate dielectric has been developed. The In0.2Ga0.8As-channel NMOSFET with a 4 μm gate length and a 100 μm gate width exhibits a drain current of 1.5 mA/mm at Vg=4V and Vd=2V, a low gate leakage of <10-7A/cm2 at 1 MV/cm, an extrinsic transconductance of 1.7 mS/mm at Vg=3V, Vd=2V, and an on/off ratio of ~105 in drain current. Lower off-currents of ~10-5-10-6 mA/mm were measured on GaAs and In0.2Ga0.8As-channel NMOSFETs comparing with most of the previously results. Moreover, the split-CV and IV results certainly demonstrate the inversion n-channel on the TiN/GGO/In0.2Ga0.8As/GaAs NMOSFETs and the strong evidence of unpinned interface between GGO and In0.2Ga0.8As. But the split-CV results on TiN/GGO/GaAs NMOSFET indicate that the responding amount of carriers in the inversion region is not identical with that in the accumulation region in this work.