Theoretical investigations on exploring Si-based heterostructures with cubic and ground-state perovskites

Abstract

First principles calculations in the framework of density functional theory (DFT) are performed to exploit replaceable perovskite oxides against the instability of traditional cubic SrTiO₃ grown on silicon substrate. In this work, we consider more thermostable CaTiO₃ and CaZrO₃ with cubic and ground-state phase as the candidates to perform the gate dielectric. After the calibration of total energy and lattice transformation of ground-state perovskites to match with Si substrate, three categories of 2 × 2 heterostructures have been constructed and investigated through the geometrical change, atom displacement around interfacial layer, total energy and electronic structure change, under the variations on perovskite species, the concentration of interfacial layer and the thickness of perovskite film. And the results demonstrate that the category with half a monolayer of Ca/Sr atoms in interfacial layer and two unit-cell perovskite thicknesses show the type-I band alignment through their band alignment. Among this category, the heterostructure with Pnma CaZrO₃ shows semiconductivity and excellent electrical property with larger band offset for the candidate of gate dielectric. This work provides a creative perspective to expand the perovskite diversity for the booming growth of integrated circuit technology.