MULTILEVEL FLUSH EEPROM CELL AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a multilevel flush EEPROM cell whose operation time can be shortened when programming and also provide a method of manufacturing the same. SOLUTION: The EEPROM cell comprises a floating gate 3 which is so formed as to be electrically isolated from a silicon substrate 1 by means of a tunnel oxide film 2 formed on the lower face of the floating gate 3, a first dielectric film 4 which is formed on the upper face of the floating gate 3, a first control gate 5 which is electrically isolated from the floating gate 3 by means of the first dielectric film 4 and which is formed on the upper face of the first dielectric film 4, a second dielectric film 6 formed on the side face and upper face of the first control gate 5, a second control gate 7 which is electrically isolated from the first control gate 5 by means of the second dielectric film 6 and which is formed on the side face and upper face of the second dielectric film 6, and a source and drain formed by a self-alignment process at the edges of the second control gate 7.