Influence of the growth conditions on the LaAIO 3 /SrTiO 3 interface electronic properties

The effects of oxygen pressure during the growth of LaAlO 3 on (001) SrTiO 3 , 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 LaAlO 3 layer thicknesses between 5 and 10 unit cells and growth pressures between 10 − 4 and 10 −2 mbar, the LaAlO 3 /SrTiO 3 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 SrTiO 3 crystal. These vacancies could be removed by post-deposition annealing in 0.2 bar of O 2 at ∼530 ° C. At a growth pressure of 10 − 4 mbar, the electronic properties of samples with ultra-thin LaAlO 3 layers (2 to 3 unit cells thick) were found to depend markedly on the post-annealing step.