Passivation of In0.53Ga0.47As/ZrO2 interfaces by AlN atomic layer deposition process

Reducing defects at III-V/high-k interfaces is essential for optimizing devices built on these materials. Here, the role of an interfacial AlN process at In0.53Ga0.47As/ZrO2 interfaces is investigated by hard x-ray photoelectron spectroscopy (HAXPES) and capacitance/voltage (C-V) measurements. C-V measurements show a significant reduction in the density of interface traps with the interfacial AlN process and a capping TiN layer. To elucidate the specific role of the AlN process, blanket films with various deposition processes are compared. The AlN process alone (without subsequent dielectric deposition) reduces InGaAs oxide levels below the HAXPES detection limit, even though the AlN is ultimately found to be oxidized into AlOx with only trace N incorporation, yet AlN passivation provides a lower Dit (density of interface traps) when compared with an H2O-based Al2O3 deposition. The AlN process does not passivate against re-oxidation of the InGaAs during an O3 based ZrO2 deposition process, but it does provide passivation against As-As development during subsequent TiN deposition. The role of chemical defects in the C-V characteristics is also discussed.