Early stage heteroepitaxial growth of SrRuO3 films on SrTiO3 (001) depending on the growth temperature during pulsed laser deposition

The growth behavior of ultrathin (∼5 nm) SrRuO3 films prepared by pulsed laser deposition (PLD) on SrTiO3 (001) was investigated particularly as a function of growth temperature mainly using synchrotron X-ray diffraction. At a critical growth temperature (∼500 deg C), below which no crystallization occurs, an epitaxial SrRuO3 film starts to grow with a broad distribution of single (110) domain along the film growth direction maintaining the epitaxial relationship of SrRuO3[001]/SrTiO3[100] and SrRuO3[-110] SrTiO3[010]. Its in-plane and out-of-plane crystal alignments improve sharply when a higher growth temperature of 600 deg. C is applied, presumably due to the more thermal energy supplied to the substrate. However, more increase of the growth temperature to 650 deg. C results in no enhancement of atomic ordering but a rougher surface, suggesting that a careful adjustment in the growth temperature is needed to grow an epitaxially well aligned SrRuO3 film possessing a smooth surface