Methods are described for operating a FeRAM and other such memory devices
in a manner that avoids over-voltage breakdown of the gate oxide in
memory cells along dummy bit lines used at the edges of memory arrays,
the methods comprising floating the dummy bit line during plate line
pulsing activity. In one implementation of the present invention the
method is applied to a FeRAM dummy cell having a plate line, a dummy bit
line, a pass transistor, and a ferroelectric storage capacitor. The
method comprises initially grounding the dummy bit line as a preferred
pre-condition, however, this step may be considered an optional step if
the storage node of the storage capacitor is otherwise grounded. The
method then comprises floating the dummy bit line, activating a word line
associated with the memory cell, and pulsing the plate line. Alternately,
the method comprises applying a positive voltage bias to the dummy bit
line in place of, or before floating the dummy bit line. The method may
further optionally comprise grounding the dummy bit line after pulsing
the plate line, and optionally disabling the word line after grounding
the dummy bit line to precondition the cell for the next memory
operation.