Al[sub 2]O[sub 3]-Ta[sub 2]O[sub 5]-ZrO[sub 2] Thin Films Having High Corrosion Resistance to Strong Acid and Alkali Solutions

Abstract

In order to develop an insulator film for an electrolyte-insulator- semiconductor capacitor pH sensor which can be used in a wide pH range, the corrosion resistance of Al 2 O 3 -Ta 2 O 5 -ZrO 2 films formed by metallorganic chemical vapor deposition has been investigated. Dissolution rates of the films deposited on a Pt substrate were measured by ellipsometry in 6 M HCl and 1 M NaOH solutions. The films with the cationic mole fraction of Al, X Al , smaller than 0.4, the cationic mole fraction of Ta, X Ta , larger than 0.3, and the cationic mole fraction of Zr, X Zr , larger than 0.3 showed high corrosion resistance against both solutions. © 2005 The Electrochemical Society. All rights reserved.