Self-aligned inversion n-channel In_(0.2)Ga_(0.8)As/GaAs metal-oxide-semiconductor field-effect-transistors with TiN gate and Ga_2O_3(Gd_2O_3) dielectric

摘要

A self-aligned process for fabricating inversion n-channel metal-oxide-semiconductor field-effect-transistors (MOSFET's) of strained In_(0.2)Ga_(0.8)As on GaAs using TiN as gate metal and Ga_2O_3(Gd_2O_3) as high k gate dielectric has been developed. A MOSFET with a 4 μm gate length and a 100 μm gate width exhibits a drain current of 1.5 mA/mm at V_g = 4 V and V_d = 2 V, a low gate leakage of < 10~(-7) A/cm~2 at 1 MV/cm, an extrinsic transconductance of 1.7 mS/mm at V_g = 3 V, V_d = 2 V, and an on/off ratio of ～10~5 in drain current. For comparison, a TiN/Ga_2O_3(Gd_2O_3)/In_(0.2)Ga_(0.8)As MOS diode after rapid thermal annealing (RTA) to high temperatures of 750 ℃ exhibits excellent electrical and structural performances: a low leakage current density of 10~(-8)-10~(-9) A/cm~2, well-behaved capacitance-voltage (C-V) characteristics giving a high dielectric constant of ～16 and a low interfacial density of state of ～(2～6) × 10~(11) cm~(-2) eV~(-1), and an atomically sharp smooth Ga_2O_3(Gd_2O_3)/In_(0.2)Ga_(0.8)As interface.