As post-Si era for digital device is incipient, In0. 53Ga0. 47As is good candidate among n-type active channels with high electron mobility but-unlike Si-it lacks a well-established technology for dielectric gating which may bear aggressive device scaling. Here we propose a viable route for the atomic layer deposition (ALD) of high-κ dielectrics taking advantage from the well-known self-cleaning effect of the trimethylaluminum (TMA) precursor on the III-V compound surfaces. In this respect, the incorporation of Al2O3 cycles both as pre-conditioning surface treatment and inside the ALD growth of a MO2 host matrix (M= Zr, Hf) is here investigated. Al: MO2/In0. 53Ga0. 47As heterojunctions have been scrutinized by in situ spectroscopic ellipsometry and ex situ chemical depth-profiling analysis which validate a good physical quality of the oxide and elucidate the effect of the pre-conditioning cycles at the interface level. The …