Ann A Koss

US Patent:

40782840, Mar 14, 1978

Filed:

Apr 4, 1977

Appl. No.:

5/784293

Inventors:

Raymond G. Capek - Elmhurst IL
Ann A. Koss - Elmwood Park IL
Frank T. Takahashi - Chicago IL

Assignee:

Zenith Radio Corporation - Glenview IL

International Classification:

H01L 4122

US Classification:

29 2535

Abstract:

A method of fabricating a lead titanate piezoelectric surface acoustic wave substrate comprises combining lead oxide, titanium tetra-n-butoxide, lanthanum oxide, and manganese dioxide, with a hydrocarbon solvent and adding water to the combination to form a slurry in which titanium polyester is precipitated unto the lead oxide and lanthanum and manganese oxides. The slurry is dried by heating to a temperature sufficient to remove the liquids therefrom but below the temperature at which an exothermic reaction between the included hydrogen, oxygen and carbon occurs. A first calcining operation produces the exothermic reaction and forms lead titanate after which the lead titanate is heated to and maintained at a temperature above that produced by the exothermic reaction. The lead titanate is then ground to produce powdered lead titanate and a second calcining is carried out to produce structural annealing of the powdered lead titantate. Binder materials are added and the combination of powdered lead titanate and binder materials is cold-pressed into substantially planar substrates.