The effects of Sr/Ti ratio on the step coverage of SrTiO/sub 3/ thin films fabricated using ECR-PEMOCVD

SrTiO/sub 3/ thin films were deposited on Si(p-type 100), Pt(1000 /spl Aring/)/SiO/sub 2//Si and stepped Pt(800 /spl Aring/)/SiO/sub 2//Si substrates using ECR-PEMOCVD to study the effects of the deposition temperature and the composition on the properties of SrTiO/sub 3/ thin films. The crystallinity and the dielectric properties of SrTiO/sub 3/ thin films were improved as the deposition temperature increased. But we could observe a distinct correlation not between the step coverage and the deposition temperature but between the step coverage and the composition. The composition of the film was changed by changing the flow rate of carrier gas of one precursor but fixing the other, being the deposition temperature fixed at 550/spl deg/C. The step coverage was improved as the composition (Sr/Ti ratio) increased up to the stoichiometric composition, and showed a saturated value of about 55% as the Sr/Ti ratio increased beyond the stoichiometric composition. This correlation was speculated using the sticking coefficients of the precursor vapors.