A low voltage (e.g. of the order of or one to three volts) instead of an
intermediate V.sub.PASS voltage (e.g. of the order of five to ten volts)
is applied to word line zero immediately adjacent to the source or drain
side select gate of a flash device such as a NAND flash device and one or
more additional word lines next to such word line to reduce or prevent
the shifting of threshold voltage of the memory cells coupled to word
line zero during the programming cycles of the different cells of the
NAND strings. This may be implemented in any one of a variety of
different self boosting schemes including erased areas self boosting and
local self boosting schemes. In a modified erased area self boosting
scheme, low voltages are applied to two or more word lines on the source
side of the selected word line to reduce band-to-band tunneling and to
improve the isolation between two boosted channel regions. In a modified
local self boosting scheme, zero volt or low voltages are applied to two
or more word lines on the source side and to two or more word lines on
the drain side of the selected word line to reduce band-to-band tunneling
and to improve the isolation of the channel areas coupled to the selected
word line. Different intermediate boosting voltage(s) (e.g. of the order
of five to ten volts) may be applied to one or more of the word lines
adjacent to the selected word line (that is the word line programming the
selected transistor), where the boosting voltage(s) applied to the word
line(s) adjacent to the selected word line are/is different from that or
those applied to other unselected word lines.