[54] MULTI-FUNCTIONAL MULTILAYER DEVICE AND METHOD FOR MAKING
[75] Inventors: Tomohiro Sogabe; Yasushi Enokido,
both of Chiba, Japan
[73] Assignee: TDK Corporation, Tokyo, Japan
[21] Appl. No.: 935,135
[22] Filed: Sep. 22, 1997
[30] Foreign Application Priority Data
Oct. 18, 1996 [IP] lapan 8-297438
[51] Int. CI.6 H01G 4/228; H01G 4/06;
H01C 7/10
[52] U.S. CI 361/306.3; 361/311; 361/313;
361/321.2; 361/322; 338/20; 338/21
[58] Field of Search 361/306.3, 305,
361/307, 308, 309, 311-313, 321.1, 321.2, 321.4, 321.5, 322; 338/20, 21; 333/181,
184
[56] References Cited
U.S. PATENT DOCUMENTS
5,072,329 12/1991 Galvagni 321/321
5,119,062 6/1992 Nakamura et al 338/20
5,548,474 8/1996 Chen et al 361/313
5,672,220 9/1997 Omori et al 156/89
5,739,742 4/1998 Iga et al 338/21
FOREIGN PATENT DOCUMENTS
63-32911 2/1988 Japan .
Primary Examiner—Bot L. Ledynh
Assistant Examiner—Anthony Dinkins
Attorney, Agent, or Firm—Obion, Spivak, McClelland,
Maier & Neustadt, PC.
[57] ABSTRACT
In a multi-functional multilayer device including a body (10) having a varistor section (2) and a capacitor section (3) stacked and integrated therewith, the adhesion between a varistor layer and a dielectric layer is improved when the varistor layer (22) contains zinc oxide as a main component and at least one lanthanide oxide as an auxiliary component, and the dielectric layer (32) contains titanium oxide or lanthanum/titanium oxide as a main component. The device experiences little warpage upon firing when glass is added to the dielectric layer. A high resistivity intermediate layer (5) disposed between the varistor and capacitor sections (2 and 3) prevents the deterioration or loss of varistor and capacitor properties by interdiffusion of elements between the varistor and capacitor sections.
12 Claims, 5 Drawing Sheets
