Analysis of III–V Oxides at High-K/ingaas Interfaces Induced by Metal Electrodes

Formation of III-V oxides at high-k/InGaAs interface was systematically investigated by means of physical and electrical characterizations. We found that, despite previous reports, a well-controlled remote oxidation of InGaAs surfaces via metal/high-k stacks effectively passivates electrical defects at high-k/InGaAs interfaces. Ultrathin regrown III-V oxides (similar to 0.5 nm) caused by oxygen diffusion from the thin Pd (10 nm thick) electrode proved beneficial in achieving superior interface quality through detailed studies with varying structures of metal electrodes. The chemical bonding states of the ultrathin regrown III-V oxides were identified as In-As-O and Ga-As-O bonds, and there were rarely direct bonds between indium or gallium and oxygen at the initial oxidation reaction. On the basis of these findings, we propose a remote oxidation model at the high-k/InGaAs interfaces and discuss physical origins of the improved and degraded interface quality caused by the interlayer growth. (c) 2019 The Japan Society of Applied Physics