Patent ID: 7326991
Filing Date: 2008-02-05
Classification: G11C,H01L

Abstract:
1. A method of reading a nonvolatile semiconductor memory having a memory cell, the method comprising: providing a semiconductor substrate having a pair of trenches formed on a surface thereof; first selective gate electrodes formed adjacent each other in said pair of trenches through the intervention of a first insulating film to form selective transistors, respectively; a second electrode that is a floating gate formed on the semiconductor substrate between the trenches through the intervention of a second insulating film; and a third electrode formed on the floating gate through the intervention of a third insulating film, and wherein the floating gate of said memory cell is centrally located between a pair of the first selective gate electrodes; and applying a voltage higher than a threshold value of the selective transistors to both of the first selective gate electrodes at the same time so that the same voltage is applied to both of the first selective gate electrodes at the same time, respectively, to change the two selective transistors into the ON state so that the two selective transistors are in the ON state at the same time, thereby reading the memory cell.