RF Sputtered Strontium Titanate Films

Two deposition parameters are important in rf sputtering of SrTiO
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films: the oxygen-argon content ratio, and the substrate temperature. More than 1% oxygen is needed to produce insulating films; the exact percentage required depends on system cleanliness. Both dielectric constant and crystallite size increase with increasing substrate temperature. Films of 2400 Å deposited at 500°C on gold have a dielectric constant of 200. The dc conductivity closely follows the Poole-Frenkel model. Two dielectric loss peaks are believed to be caused in part by an oxygen deficient region near one electrode. The variation in the dielectric constant κ with electric field is similar to that observed in bulk material.