Achieving 1nm capacitive effective thickness in atomic layer deposited HfO2 on In0.53Ga0.47As

Abstract

A capacitive effective thickness (CET) value of $1.0\mathrm{nm}$ has been achieved in atomic layer deposited (ALD) high $\kappa$ dielectrics $\mathrm{Hf}{\mathrm{O}}_2$ on ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}∕\mathrm{In}\mathrm{P}$ . The key is a short air exposure under $10\min$ between removal of the freshly grown semiconductor epilayers and loading to the ALD reactor. This has led to minimal formation of the interfacial layer thickness, as confirmed using x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. The measured electrical characteristics of metal-oxide-semiconductor diodes of $\mathrm{Au}∕\mathrm{Ti}∕\mathrm{Hf}{\mathrm{O}}_2\left(4.5\mathrm{nm}\right)∕{\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ showed a low leakage current density of $3.8\times {10}^{-4}\mathrm{A}∕{\mathrm{cm}}^2$ at $V_{\mathrm{FB}}+1\mathrm{V}$ , which is about eight orders of magnitudes lower than that of $\mathrm{Si}{\mathrm{O}}_2$ with the same CET. The capacitance-voltage curves show an overall $\kappa$ value of 17–18, a nearly zero flatband shift, and an interfacial density of states $D_{\mathrm{it}}$ of $2\times {10}^{12}{\mathrm{cm}}^{-2}{\mathrm{eV}}^{-1}$ .