Diagnosis of oxidation reactions in metalorganic chemical vapor depositionof (Ba,Sr)TiO3 films by in situ Fourier transform infrared spectroscopy

We studied the oxidation reactions of source Ti(t-BUO)(2)(DPM)(2) and Sr(DP M)(2) molecules during metalorganic chemical vapor deposition (MOCVD) by in situ Fourier transform infrared spectroscopy (FT-IR). We used O-2 and N2O gases as oxidizing agents and investigated the difference in oxidation effe ct between the two gases. From measurements of IR absorption spectra, we fo und that O-2 is more reactive than N2O in the gas phase, and selectively at tacks low-electron-density sites in the source, molecules. We deposited str ontium oxide and (Ba,Sr)TiO3 films in O-2 and N2O ambients, and investigate d the relationship between the qualities of deposited films and the gas-pha se reactions measured by FT-IR spectroscopy. In terms of the suppression of carbon contamination and the increase in the Ti/(Ba+Sr) atomic ratio, we f ound that O-2 is more suitable than N2O for the deposition of (Ba,Sr)TiO3 f ilms.