IMPROVED SPLIT GATE TYPE NON-VOLATILE FLASH MEMORY CELL AND ARRAY WHICH HAVE FLOATING GATE, CONTROL GATE, SELECTION GATE, AND ERASE GATE WITH OVERHANG ON FLOATING GATE, AND METHOD FOR MANUFACTURING

摘要

PROBLEM TO BE SOLVED: To improve the efficiency of erasing a cell by the specific dimensional relation of an erase gate with a floating gate.

SOLUTION: An improved split gate type non-volatile memory cell having in a substrate a second conductivity first region, a second conductivity second region, and a channel region between the first region and the second region is formed in a substantially single crystal substrate of the first conductivity type. The cell has a selection gate on the upper portion of the channel region, a floating gate on another portion of the channel, a control gate on the floating gate, and an erase gate adjoining the floating gate. The erase gate has an overhang extending over the floating gate. The ratio of the dimension of the overhang against the dimension of a separation in the vertical direction between the floating gate and the erase gate is in between about 1.0 and 2.5.

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