LOWER ELECTRODE FOR FERROELECTRIC MEMORY, FERROELECTRIC CAPACITOR USING IT, AND METHOD OF MANUFACTURING LOWER ELECTRODE

摘要

PROBLEM TO BE SOLVED: To provide a lower electrode for ferroelectric thin film capacitor that can reveal a high ferroelectric property, and to provide a capacitor using the electrode and a method of manufacturing the electrode.;SOLUTION: The uppermost part of this lower electrode which comes into contact with a ferroelectric substance is constituted of a polycrystalline film of a noble metal and crystal grains constituting the polycrystalline film are oriented. The (111)-orientation axis of the crystal grains is inclined with respect to the (111)-orientation surface of the polycrystalline film by 5-20C. At the time of producing the lower electrode for ferromagnetic memory, a substrate, an SiO₂ layer, a Ti layer, and the polycrystalline film of the noble metal are laminated upon another in this order and, after the Ti layer is formed, heat treatment is performed for 20-60 minutes under an oxygen-coexisting condition or an oxygen atmosphere of 0.01 MPa in pressure at a temperature of 800-1,200C. Thereafter, a ferroelectric thin film having the composition of SrxBiyTa₂O₉ (wherein, x denotes 0.6 and 0.8 and y denotes 2.05 and 2.4) is provided on the electrode film composed of the noble metal.;COPYRIGHT: (C)2004,JPO