Development of integrated heterostructures on silicon by MBE

Abstract

Heteroepitaxy of thin films of perovskite type oxides have been demonstrated on silicon (1 0 0) substrates by molecular beam epitaxy. RHEED has been used extensively to calibrate the relative fluxes and also to monitor the growing surface and adjust the stoichiometry during deposition. SrTiO 3 (STO) grows epitaxially on silicon with SrTiO 3(0 0 1)//Si(0 0 1) and SrTiO 3[1 0 0]//Si[1 1 0]. By optimising the deposition parameters, a crystalline transition across the oxide/Si interface can be obtained. An amorphous SiO 2 interfacial layer can also be formed between the oxide and silicon substrate during the deposition as a result of oxygen diffusion through the oxide layer. By adjusting the deposition parameters, the thickness of the amorphous layer can be controlled. The SrTiO 3/Si substrate can be used as a pseudo-substrate for deposition of a number of other oxides or semiconductors for multifunctional device applications.