Preparation of SrTiO₃ Films on 8-Inch Wafers by Chemical Vapor Deposition

SrTiO 3 films were grown on 8-inch-diameter Si substrates by chemical vapor deposition [CVD] using bis(dipivaloylmethanato) strontium [ Sr(DPM) 2 ], titanium tetraisopropoxide [ Ti(OiPr) 4 ] and O 2 . We have developed an oil-circulating showerhead-type nozzle to prevent condensation and decomposition of source materials. Conditions of supplying Sr(DPM) 2 were investigated with respect to cylinder pressure and the charge in the cylinder, using a simple vapor transport system. The deposition rate of SrTiO 3 films on 8-inch wafers was improved to 2 nm/min by increasing the charge in the source cylinder and decreasing the cylinder pressure. A thickness uniformity of 3.4% and a composition uniformity of 4.6% were obtained by complete mixing of gases. A step coverage of 85% was obtained using Sr(DPM) 2 , titanyl bis(dipivaloylmethanato) [ TiO(DPM) 2 ] and N 2 O.