Influence of high temperature processing of sol–gel derived barium titanate thin films deposited on platinum and strontium ruthenate coated silicon wafers

Abstract

Thin films of barium titanate (BTO) of 200nm thickness, derived from an alkoxide–carboxylate sol–gel process, were deposited on Pt/Ti and SrRuO3/ZrO2–8%Y2O3 coated Si wafers. Films with a dense columnar microstructure were obtained by repeated deposition of thin amorphous layers from low-concentrated sols, and crystallization at 800°C. This method added 10nm thickness to the crystalline BTO film in each deposition step. The harsh processing conditions had a negative impact on the platinized silicon wafers, where Pt–Si silicides were formed. This led to diffusion of Si into BTO and interfacial silicate formation. The interfacial silicate layer was the cause of deteriorated dielectric and ferroelectric properties of the BTO layer. Use of SrRuO3/ZrO2–8%Y2O3/Si substrates solved the problem. No diffusion of Si was observed, and BTO films with good dielectric and ferroelectric properties were obtained.