Diffusion induced amorphization in the crystalline SrTiO3 thin films grown on Si (1 0 0) investigated by combinatorial method

Interface structures of SrTiO3 (STO)/Si were investigated systematically using combinatorial method with growth temperature gradient in pulse laser deposition (PLD) and cross-sectional high-resolution transmission electron microscopy (HRTEM). Besides SiO2 interfacial layer, another amorphized STO layer which lying on the SiO2 interfacial layer was also observed in the crystalline STO thin films grown on Si (1 0 0) at growth temperatures above 600 °C. From the growth condition dependence studies on the formation of amorphized STO layers and the electron energy loss spectroscopy measurements, the origin of the amorphization was concluded as the diffusion of Si from substrate. This is the first observation of a diffusion induced amorphization phenomenon in the crystalline STO thin films grown on Si (1 0 0). Our results show that at higher growth temperatures, the interface structures of STO/Si are dominated by the diffusion of Si from the Si substrates.