Development of integrated hetero structures on silicon by MBE

Heteroepitaxy of thin films of perovskite type oxides have been demonstrated on silicon (10 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. SrTiO3 (STO) grows epitaxially on silicon with SrTiO3(0 0 1)//Si(0 0 1) and SrTiO3[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 SiO2, 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 SrTiO3/Si substrate can be used as a pseudo-substrate for deposition of a number of other oxides or semiconductors for multifunctional device applications. (C) 2002 Elsevier Science B.V. All rights reserved.