MICROSTRUCTURES AND INTERDIFFUSIONS OF PT/TI ELECTRODES WITH RESPECT TO ANNEALING IN THE OXYGEN AMBIENT

The microstructural variation and the interdiffusion of Pt (80 nm)/Ti (70 nm/SiO2/Si during annealing in O-2 were investigated using Auger electron spectroscopy, x-my diffraction, transmission electron microscopy, and scanning electron microscopy. While the as-deposited and 400 degrees C annealed samples showed well-defined layer structures without any significant interfacial reaction, the degree of oxidation remarkably increased with increasing temperature above 500 degrees C. The PtTi alloy phase with Pmma structure (AuCd type) was observed from the 500 degrees C annealed sample. Drastic interdiffusion occurring above 600 degrees C changed the Pt/Ti bilayer into a very entangled structure. Some TiO2 phases were exposed to the ambient between Pt hillocks. In addition, a small amount of Pt-silicide was found near the TiOx/SiO2 interface.