Film growth on single MgO and SiO2 covered si substrate by pulsed laser deposition

STO and subsequent YBCO thin films with different orientations have been grown on a single crystal MgO (100) substrate as well as a MgO on a 400nm amorphous SiO2 covered Si (100) substrate using pulsed laser deposition (PLD) technique. Cross-sectional transmission electron microscopy (TEM) showed an epitaxial growth of highly c-axis oriented YBCO(001)/STO(100) on a single crystal MgO (100). TEM investigation on MgO/SiO2 interface revealed a columnar growth of MgO film with a certain thin interlayer existing between SiO2 and MgO indicating interfacial reaction between SiO2 and MgO. Chemical reaction may be possible at the interface when films are hold at high temperature based on the calculation of Gibbs free energy. Auger electron spectroscopy (AES) showed that an uphill diffusion of Ba from YBCO occured during deposition and post thermal treatment processes.