A configuration memory cell ("CRAM") for a field programmable gate array
("FPGA") integrated circuit ("IC") device is given increased resistance
to single event upset ("SEU"). A portion of the gate structure of the
input node of the CRAM is increased in size relative to the nominal size
of the remainder of the gate structure. Part of the enlarged gate
structure is located capacitively adjacent to an N-well region of the IC,
and another part is located capacitively adjacent to a P-well region of
the IC. This arrangement gives the input node increased capacitance to
resist SEU, regardless of the logical level of the input node. The
invention is also applicable to any node of any type of memory cell for
which increased resistance to SEU is desired.