Eur. Phys. J. B (2017) 90: 178
https://doi.org/10.1140/epjb/e2017-80168-6

Regular Article

Stability and band offsets between Si and LaAlO₃

¹ School of Physics, China University of Mining and Technology, Xuzhou 221116, P.R. China
² School of Physics, The University of Sydney, Sydney, New South Wales 2006, Australia
³ School of Mathematics, China University of Mining and Technology, Xuzhou 221116, P.R. China
⁴ School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, P.R. China

^a e-mail: jlwang@cumt.edu.cn
^b e-mail: catherine.stampfl@sydney.edu.au

Received: 21 March 2017
Received in final form: 17 May 2017
Published online: 25 September 2017

Abstract

The replacement of traditional SiO₂ with high-k oxides allows the physical thickness of the gate dielectric to be thinner without the tunneling problem in Si-based metal-oxide-semiconductor field-effect transistors. LaAlO₃ appears to be a promising high-k material for use in future ultra large scale integrated devices. In the present paper, the electronic properties of Si/LaAlO₃ (001) heterojunctions are investigated by first-principles calculations. We studied the initial adsorption of Si atoms on the LaAlO₃ (001) surface, and found that Si atoms preferentially adsorb on top of oxygen atoms at higher coverage. The surface phase diagrams indicate that Si atoms may substitute oxygen atoms at the LaO-terminated surface. The band offsets, electronic density of states, and atomic charges are analyzed for the various Si/LaAlO₃ heterojunctions. Our results suggest that the Si/AlO₂ interface is suitable for the design of metal oxide semiconductor devices because the valence and conduction band offsets are both larger than 1 eV.