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

Abstract

A novel deposition sequence has been developed for the growth of carbon-free, amorphous titanium dioxide thin films on p-type Si(100) using titanium tetrakis–isopropoxide (TTIP) as the metalorganic precursor. The deposition process occurs in an ultra-high vacuum chamber and consists of three stages. Initially, a continuous layer of titanium was deposited on silicon at a substrate temperature of 650 K using a Ti sublimator. The substrate temperature was then lowered to 300 K and the titanium layer was oxidized using a gas phase oxygen source to form a TiO x buffer layer. Subsequently, a TiO 2 thin 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 that at the process temperature, titanium grows on silicon according to the Stranski–Krastanov mode, which permits the uniform growth of the titanium layer. Finally, X-ray diffraction (XRD) studies show that the thermal decomposition of TTIP produces amorphous TiO 2 at 650 K. This unique process allows for the production of a high-quality amorphous titanium dioxide thin film without interfacial carbon contamination.