A semiconductor memory device includes a field-effect transistor provided
on a surface of a P-type transistor substrate. The field-effect
transistor includes two N-type diffusion layer regions, a gate electrode,
and a charge storage section. By applying a reference voltage to one of
the N-type diffusion layer regions, a voltage higher than the reference
voltage to the other of the N-type diffusion layer regions, a voltage
lower than the reference voltage to the gate electrode, and a voltage
higher than the reference voltage to the P-type semiconductor substrate,
holes are injected into the charge storage section. Because the forward
voltage is applied to a PN junction between one of the N-type diffusion
layer regions and the P-type semiconductor substrate, it is possible to
inject the holes into the charge storage section at the voltages lower
than the voltages required if the forward voltage is not applied.
Therefore, it is possible to decrease operating voltages of the
semiconductor memory device. Thus provided is a semiconductor memory
device including a field-effect-transistor type non-volatile memory that
allows for rewrite operation at lower voltages.