Atomic-layer-deposited Al2O3/GaAs metal-oxide-semiconductor field-effect transistor on Si substrate using aspect ratio trapping technique

Abstract

High quality GaAs epilayers grown by metal-organic chemical vapor deposition are demonstrated on a SiO2-patterned silicon substrate using aspect ratio trapping technique, whereby threading dislocations from lattice mismatch are largely reduced via trapping in SiO2 trenches during growth. A depletion-mode metal-oxide-semiconductor field-effect transistor (MOSFET) is demonstrated on a n-doped GaAs channel with atomic-layer deposited Al2O3 as the gate oxide. The 10 μm gate length transistor has a maximum drain current of 88 mA/mm and a transconductance of 19 mS/mm. The surface mobility estimated from the accumulation drain current has a peak value of ∼500 cm2/Vs, which is comparable with those from previously reported depletion-mode GaAs MOSFETs epitaxially grown on semi-insulating GaAs substrates.