A programmable element including a semiconductor material doped with a dopant
that
alters the resistance of the element when exposed to actinic radiation. Rather
than producing a mechanical deformation, the radiation rearranges the bonding configuration
of the dopant in the element, allowing it to be placed on a chip in close proximity
to other device structures without risking damage to those structures. After formation,
the programmable element is subjected to a laser anneal process in which the dopant
is electrically activated. The activation process allows the dopant to donate a
charge carrier to the crystal structure. Rapid cooling following laser anneal preserves
the desired bonding configuration of the dopant produced in the programmable element.
Laser anneals have been shown to reduce the resistivity of a programmable element
by at least a factor of two.