Effect of annealing temperatures on phases and microstructures of Pt and Pt/Ti bottom electrodes for ferroelectric thin films

Pt and Pt/Ti electrodes were dc-sputtered on SiO₂/Si substrates. As-deposited samples were thermal-treated at various temperatures by the common thermal annealing (CTA) process and the rapid thermal annealing (RTA) process respectively. Phase identifications and microstructures were carried out by using XRD and SEM techniques. The qualitative analysis of the compositions was held by an energy dispersive spectrum. The results indicated that the crystal grains of the Pt thin films changed from small to large and from uniform to local collective, and then separated islands with increasing the annealing temperature. The Ti layer can improve the stability of the Pt films at high temperature and the adhesion of the Pt films on the oxidized Si wafers. Adopting the RTA process can promote the uniformity of the Pt films annealed at high temperature. The morphologies and microstructures of the Pt and Pt/Ti electrodes have important effects on the electric properties of ferroelectric PLT thin films deposited on them.