SrBiTaO dielectric, dielectric thin film, constituent and thin film formation manner null for thin film formation

摘要

PURPOSE: To obtain a dielectric substance which has a large remanence value without fatigue in its film layer by specifying its composition to a unit comprising Sr-Bi-Ta-O. ;CONSTITUTION: An Sr-Ti-Ta-O dielectric substance which comprises a complex oxide of Sr-Bi-Ta, is represented by the formula where 0x1 and (y) represents the total of oxygen atoms following each of the metals. This dielectric substance is obtained by exchanging a part of Sr with Bi in order to increase the ferroelectric properties of conventional SrBi₂O₉, and shows an increased remanence value and a reduced film layer fatigue. The dielectric substance is preferably used as a thin film layer of 10nm-1μm, more preferably 80-800nm. The film layer thinner than 10nm is different to keep satisfactory insulation, while thicker than 1μm roughens the surface because of excessively large grain growth. The ferroelectric material is used as a semiconductor memory to give excellent devices free from film layer fatigue.;COPYRIGHT: (C)1996,JPO