Inversion-mode InxGa1-xAs MOSFETs (x=0.53,0.65,0.75) with atomic-layer- deposited high-k dielectrics

High-performance inversion-type enhancement-mode (E-mode) nchannel MOSFETs on In-rich InGaAs using ALD Al2O3 as high-k gate dielectrics are demonstrated. The maximum drain current, peak transconductance, and the effective electron velocity of 1.0 A/mm, 0.43 S/mm and 1.0x10 cm/s at drain voltage of 2.0 V are achieved at 0.75-μm gate length devices. The device performance of In-rich InGaAs NMOSFETs with different indium contents, In0.53Ga0.47As, In0.65Ga0.35As and In0.75Ga0.25As, are systematically studied and compared. Deep submicron inversion-mode In0.75Ga0.25As MOSFETs with ALD high-k Al2O3 as gate dielectric are also demonstrated by the full electron beam lithography process. N-channel MOSFETs with 100 nm to 200 nm-long gates have been fabricated. At a supply voltage of 0.8 V, the fabricated devices exhibit drain currents of 260 μA/μm to 801 μA/μm and transconductances of 540 μS/μm to 950 μS/μm. Important scaling metrics, such as on/off current ratio, sub-threshold swing, and drain-induced barrier lowering are presented and their relations to the short-channel effect are discussed. Although on-state performance of InGaAs MOSFETs, such as drain current and trans-conductance, shows great opportunities for III-V MOSFET for future logic applications, great challenges could still exist on off-state performance limited by the implanted junction leakage and donar-type interface traps at high-k/InGaAs interfaces.