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:
Aug. 27, 1996
Filed:
Oct. 19, 1994
Philip J Cacharelis, Menlo Park, CA (US);
Jeffrey R Perry, Sunnyvale, CA (US);
Narasimha Narahari, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An EEPROM cell is formed in an IC chip by using only three masking steps in addition to those required for the basic CMOS transistors in the chip. A first mask layer is used to define source/drain regions of select and memory transistors within the EEPROM cell; a second mask layer is used to define a tunneling region of the memory transistor;and a third mask layer is used to define a floating gate of the memory transistor and a gate of the select transistor. A control gate of the memory transistor is formed using the same mask that is used to define the gates of the CMOS transistors. The third and fourth mask layers may also be used to form the lower and upper electrodes, respectively, of a capacitor.