In this letter, we have investigated electrical properties of metal-oxide-semiconductor (MOS) gate stack of Pt/Y2O3/In0.53Ga0.47As under different annealing conditions. We have found that proper annealing step significantly improves MOS interfacial properties of Pt/Y2O3/In0.53Ga0.47As MOS capacitors. Finally, we have realized MOS interface with a low density of trap state (D-it) of 4 x 10(12) eV(-1) . cm(-2) and hysteresis of 15 mV using postmetallization annealing at 350 degrees C. Furthermore, we also first demonstrated In0.53Ga0.47As-on-insulator (-OI) transistors with Y2O3 buried oxide layer using developed MOS interface. Fabricated In0.53Ga0.47As-OI transistors show good I-V characteristics and high peak mobility of similar to 2000 cm(2)/Vs.