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:
Nov. 21, 2000
Filed:
May. 19, 1999
Shinichiro Hayashi, Osaka, JP;
Tatsuo Otsuki, Osaka, JP;
Carlos A Paz de Araujo, Colorado Springs, CO (US);
Symetrix Corporation, Colorado Springs, CO (US);
Abstract
A ferroelectric field effect transistor memory cell includes a thin film varistor located between the gate electrode and the ferroelectric layer. The varistor protects the ferroelectric layer from disturb voltage pulses arising from memory read, write and sense operations. A second electrode is located between the thin film varistor and the ferroelectric layer. The thin film ferroelectric is positioned over the channel of a transistor to operate as a ferroelectric gate. For voltages at which disturb voltages are likely to occur, the thin film varistor has a resistance obeying a formula R.sub.d >10.times.1/(2.pi.fC.sub.F), where R.sub.d is resistivity of the thin film varistor, f is an operating frequency of said memory, and C.sub.F is the capacitance of the ferroelectric layer. For voltages at or near the read and write voltage of the memory, the thin film varistor has a resistance obeying a formula R.sub.d <0.1.times.1/(2.pi.fC.sub.F).