Thin-film dielectric and process for its production

Details Thin-film dielectric and process for its production Thin-film dielectric and process for its production

1984-10-01

1987-01-13

Griffin, Donald A.

Electricity: electrical systems and devices

Electrostatic capacitors

Fixed capacitor

252 623BT, 501136, H01G 410, C04B 3546

Patent

active

046369082

DESCRIPTION:

BRIEF SUMMARY
DETAILED EXPLANATION OF THE INVENTION

1. Field of the Invention
This invention concerns thin-film dielectrics. More specifically, it relates to thin-film dielectrics comprising a thin-film of lead titanate (hereunder called "PT") or lead titanate zirconate (hereunder called "PZT") or lanthanum-containing lead titanate zirconate (hereunder referred to as "PLZT") formed on a substrate and a process for production of those.
2. Background to the Invention
Conventionally, a dielectric at a thin-film state has been manufactured by grinding to a specified thickness a dielectric porcelain prepared by sintering a moulding formed through pressing a mixture of inorganic metallic compounds powder.
Under the conventional method, it is exceedingly difficult to produce a thin-film dielectric having a thicknesses of 100 microns or less and sufficiently high specific inductive capacity and satisfying requirements for excellent dielectric devices. Particularly, when very hard and highly sintered dielectric porcelain is ground to a desired thickness, crystal grain defects or cracks of thin-film easily occur, and so it becomes necessary to use a special instrument. Moreover, due to high sintering temperature, special and highly expensive metallic materials must be used as electrodes.
Processes for the production of a thin-film dielectric usable for a dielectric device have been studied by employing sputtering process, vacuum evaporation process, vapor growth process etc. In those processes, however, it is difficult for the product to obtain desired dielectric characteristics, because each vapor pressure of individual chemical component is different (for example, lead oxide has a specifically high vapor pressure to readily vaporize off) to make it difficult to control the process stoichiometrically, and further it is difficult to avoid appearing electro-conductive passage through out the thin-film (dielectric). Therefore, none of these process has been commercially adopted. In Japan Laid-Open Patent Tokkaisho 56-28408 (1981), a process for the production of thin-film dielectrics is proposed. In the process, a solution containing organo-metallic compounds is coated on a glass substrate by a dropping method or a dipping method, and the coated film is dried in air at ordinary temperature for 30 minutes and then heated at 110.degree. C. for 30 minutes in a thermostatic oven to complete the hydrolysis reaction. Thereafter, the coated substrate is baked by heating it to a temperature in a range of 200.degree. C.-800.degree. C. and forcedly supplying with steam in an electric furnace.
In said method, however, a uniform coating film is not obtained because the proposed organo-metallic compounds solution is excessively unstable and readily hydrolyzed by absorbing moisture in the air. In addition, it is difficult to control the condition of atmosphere, especially, the partial vapor pressure of steam in the hydrolysis and the baking process, it is so hard to decompose and eliminate hydroxyl radicals from the baked product, because in the baking process the hydrolysis (which is a process making hydroxyl radical) is conducted simultaneously. Therefore, a practical thin-film dielectric can not be manufactured because of the frequent occurrence of electro-conductive passages through the product.
It is suggested that, in said method, it is possible to place a thin-film of dielectric material on a glass substrate, but in said publication, any of specific dielectric characteristics of the thin-films obtained is not shown, and therefore, there has been no confirmation of any success in the production of thin-film dielectric usable as dielectric devices.
In Japan Laid-open Patent Tokkaisho 58-41723 (1983) and Japan Patent Application No. Tokugansho 57-152739 (1982) filed by the applicant, the production of thin-film of dielectric on the substrate by using a dielectric precursor solution is shown, but any dielectric characteristics as the thin-film dielectric is not shown.


OBJECT OF THE INVENTION

The object of this invention is to provide a th

REFERENCES:
patent: 3495996 (1970-02-01), Delaney et al.
patent: 4061583 (1977-12-01), Murata et al.
patent: 4063341 (1977-12-01), Bouchard et al.
patent: 4266265 (1981-05-01), Maher
patent: 4309295 (1982-01-01), McSweeney

Affiliated with

Also associated with

Rating

Thin-film dielectric and process for its production does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Thin-film dielectric and process for its production, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thin-film dielectric and process for its production will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2359843