Thermal lattice expansion in epitaxial SrTiO3(100) grown on Si(100) by molecular beam epitaxy was examined by in situ x-ray diffraction (XRD) at temperatures ranging from 25 °C to 1000 °C. The SrTiO3 layer thickness (~400 Å) was determined a priori by ex situ x-ray reflectivity (XRR). In addition, the SrTiO3(100) film was further characterized before and after thermal treatment by Rutherford backscattering spectroscopy in channeling geometry (RBS/C) and transmission electron microscopy (TEM). The XRD results showed that the rate of thermal expansion in epitaxial SrTiO3 in the out-of-plane direction is approximately 1.5-2.0 times the bulk value. In addition, the SrTiO3 film was seen to relax after heating. RBS/C and TEM also revealed the formation of a thick (~1000 Å), amorphous silica layer at the SrTiO3/Si interface. Interestingly, the SrTiO3 film retained its epitaxial form atop this non-templating surface while its crystalline quality improved with annealing. These results will be further discussed in the context of their potential application toward silicon-on-insulator (SOI) semiconductor architecture.
Revised: November 8, 2006 |
Published: October 1, 2006
Citation
McCready D.E., Y. Liang, V. Shutthanandan, C.M. Wang, and S. Thevuthasan. 2006.Thermal Lattice Expansion in Epitaxial SrTiO3(100) on Si(100). In Advances in X-ray Analysis, proceedings of the 55th Annual Denver X-ray Conference, August 7-11, Denver Marriott Tech Center Hotel, Denver, Colorado, U.S.A., 49, 175-179. Newton Square, Pennsylvania:JCPDS-International Centre for Diffraction Data.PNNL-SA-47577.