Combinatorial Approach to the Interface Structure Characterizations of SrTiO_3 on Si(lOO)

摘要

Interface structures of SrTiO_3/Si were investigated systematically using combinatorial method with growth temperature gradient in pulse laser deposition and cross sectional high resolution transmission electron microscopy. A combinatorial pulse laser deposition with growth temperature gradient system was employed to grow SrTiO_3 on Si (100) with various temperatures and oxygen pressures. A high throughput thin foil fabrication system, which is so called micro sampling system, was employed to fabricate thin foils for cross sectional high resolution transmission electron microscope observation. As a result, we have observed a never reported amorphized SrTiO_3 layer in the crystalline SrTiO_3 thin films grown on Si (100) at growth temperatures above 600°C. From the growth condition dependence studies on the formation of amorphized SrTiO_3 layers and the electron energy loss spectroscopy measurements, the origin of the amorphization was concluded as an effect of diffusion of Si from substrate. This is the first observation of a diffusion induced amorphization phenomenon in the crystalline SrTiO_3 thin films grown on Si (100). Our results show that at higher growth temperatures, the interface structures of SrTiO_3/Si are dominated by the diffusion of Si from the Si substrates.