Gate-induced drain leakage pre-charge in sub-block mode for three or more tier non-volatile memory structure

Abstract

An apparatus includes memory cells connected to word lines and disposed in strings each defining a channel and coupled to bit lines and a source line. The memory cells are configured to retain a threshold voltage corresponding to data states. A control means is configured to apply programming pulses followed by verification pulses of program verify voltages associated with the data states to the word lines during a program operation. The control means ramps a selected word line voltage applied to the word lines from one of the program verify voltages to approximately zero while ramping voltages applied to the bit lines and the source line to a high supply voltage during a pre-charge operation. The control means ramps an assist voltage applied to a pre-charge assist portion of the memory apparatus to generate gate-induced drain leakage current in the strings and pre-charge the channel during the pre-charge operation.