Patent ID: 6611461
Filing Date: 2003-08-26
Classification: G11C

Abstract:
A method to program verify a dual storage site MONOS memory cell using a reverse read operation, comprising:a) maintaining a first voltage coupled to a first control gate located above an unselected storage site of a MONOS memory cell to be same as for a program operation, b) lowering a second voltage coupled to a second control gate above a selected storage site of said memory cell to a value less than that used for said program operation, c) disconnecting and floating a drain diffusion and a source diffusion of said memory cell, then d) equalizing said drain diffusion voltage and said source diffusion voltage of said memory cell, e) biasing a word gate voltage of said memory cell to a third voltage higher than used for said program operation, then f) lowering said drain diffusion voltage to a value below said drain and source equalize voltage, then g) comparing said source diffusion voltage to a reference voltage.