Self-limiting growth of ultrathin Ga2O3for the passivation of Al2O3/InGaAs interfaces

Ga2O3 film growth on InGaAs substrates was investigated using an atomic layer deposition system with trimethylgallium (TMGa) and H2O as precursors. Self-limiting growth of Ga2O3 was confirmed on InGaAs substrates as well as on Si and GaAs. During initial formation of the Ga2O3 film on an InGaAs substrate, the selective self-cleaning effect of TMGa on AsOx and GaOx was observed. The insertion of ultrathin Ga2O3 into an Al2O3/InGaAs gate stack as an interfacial passivation layer proved quite effective to reduce Dit around the midgap. The Al2O3/InGaAs MISFET performance also revealed improvement of the effective mobility for both NH4OH- and (NH4)2S-treated devices.