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:
Apr. 30, 1996
Filed:
Jan. 09, 1995
Graham Wolstenholme, Boise, ID (US);
Albert Bergemont, San Jose, CA (US);
Etan Shacham, Cupertino, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A nonvolatile semiconductor memory, which includes an array of programmable transistor cells, such as EPROM or EEPROM cells, provides electrical isolation without the use of field oxide islands. The cells are arranged in X number of rows and Y number of columns with the cells in at least two of the rows being designated as select cells and the remaining cells being designated as memory cells. Control circuitry is provided for causing the select cells to supply programming voltages to selected ones of the memory cells. Alternate ones of the select cells are formed as implanted-channel select cells to provide electrical isolation for adjacent select cells which remain in the low threshold (active) state. The implanted-channel select cells are formed by implanting a material into the channel region of each of the implanted-channel select cells to increase the threshold voltage of the cells, thereby preventing the implanted channel select cells from conducting when normal operational voltages are applied.