Noriaki Tani

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.

Stability Control of Composition of RF-Sputtered Pb(Zr, Ti)O3 Ferroelectric Thin Film

The process stability of Pb(Zr, Ti)O3 (PZT) sputtering was studied by observing film composition change as a function of the process duration ( e.g. integrating sputtering time). A useful method of controlling compositional stability was developed. It was found that the existence of a potentially grounded anode was effective to prevent the large variation of Pb contents in PZT thin films and improve the process stability of PZT sputtering.

A New Perpendicular Magnetic Film of Co–O by Evaporation

A new perpendicular magnetic film has been developed by an evaporation method using room temperature substrates. The film is obtained by partially oxidating the Co film with the oxygen gas introduced during deposition. The film structure is a mixture of very fine Co grains and CoO phase. The obtained films have such superior perpendicular magnetic properties as Hc⊥=1100 Oe, Hk=5.5 kOe and 4πMs=6000 G at Co–45 at%O film composition.