SOFT PROGRAM AND SOFT PROGRAM VERIFY OF THE CORE CELLS IN FLASH MEMORY ARRAY

摘要

A method (900) and system (400) are disclosed for memory cell soft program and soft program verify, to adjust, or correct the threshold voltage (350) between a target minimum (380) and maximum (390), which may be employed in assoication with a dual bit memory cell architecture (50). The method (900) includes applying one reference voltage signal (455) to the over erased core cell, and a diference cell (480), comparing the two currents (475) produced by each, selectively verifying (485, 435) proper soft programming of one or more bits of the cell (405), determining that the dual bit memory cell is properly soft programmed (950). The method may also comprise selectively re-verifying (950, 955) proper soft programming of the cells after selectively soft programming (965) at least one or more bits (980) of the cell.