Improving the ALD-grown Y2O3/Ge interface quality by surface and annealing treatments

Abstract

Metal Oxide Semiconductor capacitors are investigated, employing ALD grown Y2O3 as gate dielectric, and n-type (100) germanium as channel substrate. The effect of post deposition annealing (PDA) in oxygen and forming gas atmosphere using a thin catalytically acting platinum (Pt)-layer on the Y2O3/Ge interface is electrically analyzed for buffered hydrofluoric (BHF) and thermally pre-treated Ge-surfaces.The Pt-assisted PDA ensures even for BHF pre-treated samples very low values for the interface trap density Dit of 1.55×1011eV−1cm−2 and low leakage current densities J of <7×10−9A/cm2 outperforming conventional PDA treatments. The interfacial formation of GeO2 and yttrium germanate after PDA is proven by using X-ray Photoelectron Spectroscopy measurements.