Reaction products and oxide thickness formed by Ti out-diffusion and oxidization in poly-Pt/Ti/SiO2/Si with oxide films deposited

In the paper, we present experimental results to enhance the understanding of Ti out-diffusion and oxidization in commercial poly-Pt/Ti/SiO2/Si wafers with perovskite oxide films deposited when heat-treated in flowing oxygen ambient. It indicates that when heat-treated at 550 and 600 8C, PtTi3+PtTi and PtTi are the reaction products from interfacial interaction, respectively; while heat-treated at 650 8C and above, the products become three layers of titanium oxides instead of the alloys. Confirmed to be rutile TiO2, the first two layers spaced by 65 nm encapsulate the Pt surface by the first layer with 60 nm thick forming at its surface and by the next layer with 35 nm thick inserting its original layer. In addition, the next layer is formed as a barrier to block up continuous diffusion paths of Ti, and thus results in the last layer of TiO2 x formed by the residual Ti oxidizing.