Katsumi Sameshima

Surface morphology of lead-based thin films and their properties

Surface morphology of lead-zirconate-titanate [PZT(52/48)] thin films prepared by sol-gel processing on Pt/Ti/ SiO2/Si substrates was studied. When the atomic ratio [Pb/(Zr+Ti)] of PZT gel films was 1, rosette structure was observed in the films after annealing at 600° C for one hour. The crystal structure of the rosette was identified as perovskite and that of the other area was nonperovskite, by electron diffraction analysis. Lead deficiency in the non-perovskite phase caused by lead diffusion into the bottom electrode was detected by energy dispersive X-ray spectroscopy and Auger electron spectroscopy. In order to prepare PZT films with a smooth surface, the following four means were efficient: addition of lead excess, rapid thermal annealing (RTA), adoption of buffer layer, and preparation of crystal nucleus on the substrate.

Micro-Patterning of PbZrxTi1-xO3 Thin Films Prepared by Photo Sensitive Sol-Gel Solution

The photo sensitivity of sol-gel solution of PbZr x Ti 1-x O 3 (PZT) was studied. A coated film of the sol-gel solution on Pt/Ti/SiO 2 /Si substrates was exposed to an excimer laser and developed with water. The film was finally annealed at 700 o C for 60 s by rapid thermal annealing (RTA). Ferroelectric perovskite phase was observed in the PZT thin films. The 130-nm-thick film showed P r of 11.2 μzC/cm 2 and E c of 93.8 kV/cm. From this process, half-micron patterns of PZT films were obtained

Preparation of (Pb, La) (Zr, Ti)O3 ferroelectric films by RF sputtering on large substrate

(Pb, La)(Zr, Ti)O 3 (PLZT) thin films were deposited on 6-inch Pt/Ti/SiO 2 /Si substrates by rf magnetron sputtering using a multichamber production system. The Pb content in PLZT films deposited at low temperature was measured by inductively coupled plasma (ICP) spectroscopy, and the structural properties of crystallized PLZT films were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A novel method for Pb content control was developed and it was found that Pb content in PLZT film could be changed by changing the electric potential of the substrate. For ferroelectric properties, only small differences were observed between the rapid thermally annealed PLZT film and furnace- annealed ones. Good uniformities of film thickness, Pb content and remanent polarization were achieved on 6-inch wafers.

Preparation of Pb(Zr,Ti)O3 films on Pt/Ti/Ta electrodes by sol-gel process

PbZr x Ti 1-x O 3 (PZT) films were prepared on Pt, Pt/Ti or Pt/Ti/Ta electrodes by the sol-gel process using rapid thermal annealing (RTA). In the case of Pt and Pt/Ti electrodes on poly-Si, thermal treatments of PZT films gave rise to interdiffusion between Pt and Si. This exerted an unfavorable influence on the preparation of PZT films with perovskite structure. The barrier effect of Ta films and the effect of Ti films on the crystallization of PZT films were investigated by X-ray diffraction (XRD) and Auger electron spectroscopy (AES). The electrical properties such as dielectric constants and P-E hysteresis curves were measured for PZT films with various Zr/Ti ratios on Pt/Ti/Ta/SiO 2 /Si(100) substrates

Lead content control of PLZT thin films prepared by RF magnetron sputtering

Abstract PLZT thin films were deposited on 6-inch Pt/Ti/SiO2/Si substrates by radio frequency (RF) magnetron sputtering using a multichamber type production system. The lead (Pb) content in low temperature deposited PLZT films was measured by ICP spectroscopy and structural properties of rapid thermally annealed PLZT films were characterized by X-ray diffraction and scanning electron microscopy. It is found that several sputtering parameters such as RF power, argon (Ar) gas flow and magnetic field were very effective to control the Pb content which is essential for obtaining good ferroelectric properties.