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:
Dec. 30, 2008
Filed:
Mar. 09, 2006
Norikatsu Takaura, Tokyo, JP;
Hideyuki Matsuoka, Nishitokyo, JP;
Motoyasu Terao, Hinode, JP;
Kenzo Kurotsuchi, Kokubunji, JP;
Tsuyoshi Yamauchi, Isahaya, JP;
Norikatsu Takaura, Tokyo, JP;
Hideyuki Matsuoka, Nishitokyo, JP;
Motoyasu Terao, Hinode, JP;
Kenzo Kurotsuchi, Kokubunji, JP;
Tsuyoshi Yamauchi, Isahaya, JP;
Hitachi, Ltd., Tokyo, JP;
Hitachi ULSI Systems Co., Ltd., Tokyo, JP;
Abstract
With a high-speed nonvolatile phase change memory, reliability in respect of the number of refresh times is enhanced. In a memory cell forming area of a phase change memory using a MISFET as a transistor for selection of memory cells, a phase change material layer of a memory cell comprising a resistor element, using a phase change material, is formed for common use. As a result, variation in shape and a change in composition of the phase change material, caused by isolation of memory cell elements by etching, are reduced, thereby enhancing reliability of memory cells, in respect of the number of refresh times.