STRUCTURE OF EPITAXIAL THIN TIO2 FILMS ON W(110) AS STUDIED BY LOW-ENERGY-ELECTRON DIFFRACTION AND SCANNING-TUNNELING-MICROSCOPY

We have studied the growth and structure of thin TiOx films on W(110) using Auger electron spectroscopy, low energy electron diffraction (LE ED), and scanning tunneling microscopy (STM). The procedure used to gr ow these films includes the deposition of Ti metal onto the W(110) sur face followed by a saturation oxygen exposure. LEED and STM reveal tha t several different ordered TiOx film structures can result depending upon the initial amount of Ti deposited and the final annealing temper ature, Specifically, the oxidation and anneal to 1350 K of a one monol ayer (ML) film of Ti resulted in the formation of a strained ML struct ure that has a distorted hexagonal lattice acid long-range order as ob served by LEED and STM. The epitaxial relationship of this 1 ML TiOx s tructure with the W(110) substrate is found to occur with a Nishiyama- Wassermann orientation. (C) 1996 American Vacuum Society.