Influence of the growth conditions on the LaAIO₃/SrTiO₃ interface electronic properties

DPMC, University of Geneva - 24 quai Ernest-Ansermet, 1211 Genève 4, Switzerland

^a claudia.cancellieri@unige.ch

Received: 6 May 2010
Accepted: 24 June 2010

Abstract

The effects of oxygen pressure during the growth of LaAlO₃ on (001) SrTiO₃, and of post-deposition annealing were investigated. While little influence on the structure was observed, the transport properties were found to depend on both growth pressure and annealing. For LaAlO₃ layer thicknesses between 5 and 10 unit cells and growth pressures between 10^{− 4} and 10⁻² mbar, the LaAlO₃/SrTiO₃ interfaces displayed similar metallic behavior with a sharp transition to a superconducting state. At an oxygen pressure of 10^{− 6} mbar oxygen vacancies were clearly introduced and extended deep into the SrTiO₃ crystal. These vacancies could be removed by post-deposition annealing in 0.2 bar of O₂ at ∼530 ^°C. At a growth pressure of 10^{− 4} mbar, the electronic properties of samples with ultra-thin LaAlO₃ layers (2 to 3 unit cells thick) were found to depend markedly on the post-annealing step.