Interface control in the chemical vapor deposition of titanium dioxide on silicon(100)

A novel deposition sequence has been developed for the growth of carbon-fre e, amorphous titanium dioxide thin films on p-type Si(100) using titanium t etrakis-isopropoxide (TTIP) as the metalorganic precursor. The deposition p rocess occurs in an ultra-high vacuum chamber and consists of three stages. Initially, a continuous layer of titanium was deposited on silicon at a su bstrate temperature of 650 K using a Ti sublimator. The substrate temperatu re was then lowered to 300 K and the titanium layer was oxidized using a ga s phase oxygen source to form a TiOx buffer layer. Subsequently, a TiO2 thi n film was deposited by MOCVD using TTIP at low temperature (below 650 K). Auger electron spectroscopy (AES) performed at each stage of growth showed no detectable carbon contamination. Additional AES measurements suggest tha t at the process temperature, titanium grows on silicon according to the St ranski-Krastanov mode, which permits the uniform growth of the titanium lay er. Finally, X-ray diffraction (XRD) studies show that the thermal decompos ition of TTIP produces amorphous TiO2 at 650 K. This unique process allows for the production of a high-quality amorphous titanium dioxide thin film w ithout interfacial carbon contamination. (C) 2000 Elsevier Science B.V. All rights reserved.