The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 01, 1990
Filed:
Jul. 05, 1989
Toshitaka Fukushima, Yokohama, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
A field programmable device such as a PROM in which a memory cell is formed from a series connection of a capacitor and a diode or FET. Programming is performed by forming a short circuit in an insulation film of the capacitor due to electrical breakdown of the capacitor. The capacitor is formed of first and second semiconductor layers and an insulation film between the two layers. The instability of short circuits due to further oxidation of the insulation film is avoided by the above described structure. The memory stored in the device is stabilized, and the reliability of the device is increased. The insulation film of the capacitor is oxidized or nitrided by ion implantation of oxygen or nitrogen into the semiconductor substrate, or polycrystalline material.