Flash Memory System Using Complementary Voltage Supplies

摘要

A non-volatile memory device comprises a semiconductor substrate of a first conductivity type. An array of non-volatile memory cells is located in the semiconductor substrate and arranged in a plurality of rows and columns. Each memory cell comprises a first region on a surface of the semiconductor substrate of a second conductivity type, and a second region on the surface of the semiconductor substrate of the second conductivity type. A channel region is between the first region and the second region. A word line overlies a first portion of the channel region and is insulated therefrom, and adjacent to the first region and having little or no overlap with the first region. A floating gate overlies a second portion of the channel region, is adjacent to the first portion, and is insulated therefrom and is adjacent to the second region. A coupling gate overlies the floating gate. A bit line is connected to the first region. During the operations of program, read, or erase, a negative voltage can be applied to the word lines and/or coupling gates of the selected or unselected memory cells.

主权项

1. A method of operating a flash memory device comprising a first set of memory cells and a second set of memory cells, the method comprising:
erasing the first set of memory cells, the erasing step comprising: applying a first negative voltage to each coupling gate of the first set of memory cells; applying a non-negative voltage to each word line and bit line of the first set of memory cells; and applying a first positive voltage to each erase gate of the first set of memory cells; and inhibiting the erasing of the second set of memory cells by applying a second positive voltage to each coupling gate of the second set of memory cells.