Flash memory device and bit line charging method thereof

Abstract

A flash memory device includes a memory string, a selection switch, a first power source and a second power source. The memory string has a plurality of memory cells. A first memory cell in the memory string is coupled to a first word line, and the first word line is selected to be a programmed word line and the first memory cell is selected to be an inhibited cell, during a first time period, the selection switch is turned on according to a selection signal, and the first power source pulls up voltages on the global bit line and the local bit line to a first voltage. During a second time period, the selection switch is turned-off according to the selection signal, a word line voltage on the first word line is pulled up to pump up the voltage on the local bit line to a second voltage.