The present patent relates to
flash memory devices with improved erase function, and method of controlling an erase operation of the same. According to the present patent, the
flash memory device includes
memory cell blocks, each having a plurality of memory cells sharing local word lines and bit lines, an X-decoder which
decodes a row address
signal and outputs the decoded
signal, a block selection unit, which selects some of the
memory cell blocks in response to the decoded
signal, and connects local word lines of the selected
memory cell blocks to corresponding global word lines, respectively, and a
high voltage generator, which generates word line bias voltages in response to one of a read command, a program command and an erase command, and supplies the generated word line bias voltages to the global word lines in response to the decoded signal, respectively, wherein the word line bias voltages, which are generated by the
high voltage generator in response to the erase command, have a positive value, respectively. Accordingly, a
positive bias voltage is applied to a global word line in an erase operation. It is thus possible to prevent a shallow erase phenomenon of non-selected memory
cell blocks due to the leakage current of pass gates.