Fabrication and characterization of thin and smooth Pt electrode and PZT thin films

Abstract

Part Ⅰ. A study on Pt thin films as bottom electrode The control of microstructure plays a key role in the properties of platinum (Pt) thin films. Pt thin films were deposited on $SiO_2$/Si substrates at 350℃ using dc magnetron sputtering system. As film thickness increased, both grain size and roughness increased. The increase of surface roughness might result from the groove deepening due to grain growth. The crystallographic texture changed from random to a strong (111) fiber texture during film thickening. The texture development was discussed in the view of the contribution of strain energy minimization and surface energy minimization to grain growth. The strain energy minimization was more contributed to the determination of crystallographic texture that the surface energy minimization in Pt thin film below 100 nm. In order to study the effect of annealing treatment, 30 nm-thick Pt thin films having 3.7Å rms roughness, they were fabricated on $SiO_x$/Si substrates at 350℃ using dc magnetron sputtering system, and annealed at 400℃ and 650℃. As annealing temperature increased, the surface roughness and the migration of Si atoms to Pt layer increased. The silicide formation was observed and analyzed by XRD, AFM, SEM and AES technique. We discuss about it in the view of the generation of Si cluster in $SiO_x$ layer with x＜2.0 near Pt layer. In order to evaluate the electrical properties, the resistivity of Pt thin films were measured. Below the critical film thickness, the resistivity increased rapidly. Part Ⅱ. A study on PZT thin films as storage media The dependence of piezoelectric properties of PZT thin films on film thickness was investigated using atomic force microscope (AFM) assisted domain imaging technique. PZT thin films were fabricated on Pt(111)/$TiO_x$/$SiO_2$/Si substrates at 375℃ by radio frequency (RF) magnetron sputtering. As the thickness of PZT thin film increased, the grain size increased and the preferred orientation of PZT thin film cha...