Templates for LaAlO_3 epitaxy on silicon

摘要

As direct epitaxy of crystalline LaAlO_3 on silicon has not been realized yet, we investigated the use of a template between the high-κ and the substrate. We performed calculations in the Density Functional Theory framework for two possible templates: a Sr_(0.5)O mono-layer and a 0.5 nm thick γ-Al_2O_3(001) layer. We firstly found that in the Sr_(0.5)O monolayer case, care must be taken for the LaAlO_3 starting sequence in order to expect good band offsets with silicon. In the γ-Al_2O_3 case, a more complex engineering of the interface is needed. Nonetheless, we found stable interfaces and a surface reconstruction in agreement with experimental observations. Moreover, these interfaces exhibit insulating properties and insight calculations for a Si-γ-Al_2O_3-LaAlO_3 superstructure lead us to a 1.9 eV conduction band offset.