The semiconductor device comprising a chalcogenide phase change material. The chalcogenide material being programmed from one resistance state to another resistance state by applying a programming current to a resistor which is in thermal contact with the chalcogenide material. The semiconductor device may be used as memory element or as a programmable fuse.

A reprogrammable switch includes a first phase-change element, a first reference element, and a second reference element. The switch includes a sense amplifier for outputting a first signal based on a comparison of a signal from the first phase-change element to a signal from the first reference element and for outputting a second signal based on a comparison of the signal from the first phase-change element to a signal from the second reference element.

Chalcogenide technology is used for radiation hardening for spaceborne systems and more particularly in C-RAM form for processors, field programmable gate arrays, startup RAMs, shadow storage and single-chip systems to protect these units.

A repair fuse element and method of construction are disclosed that eliminate or substantially reduce the disadvantages and problems associated with prior fuse elements. In one embodiment, the fuse element is constructed with a rectangular-shaped contact. The contact is made long enough so that it makes contact at each end with a metal layer, but design rule spacing is still maintained between the connections with the metal layer. The overlapping areas between the rectangular contact and the metal layers are asymmetrical. Alternatively, these overlapping areas are smaller than the design rule overlap requirements. In a second embodiment, a fuse element is constructed with a plurality of rectangular-shaped contacts. As a result, a current value that is significantly lower than conventional fuse current values, can be used to melt such a contact or blow the fuse.

A repair fuse element and method of construction are disclosed that eliminate or substantially reduce the disadvantages and problems associated with prior fuse elements. In one embodiment, the fuse element is constructed with a rectangular-shaped contact. The contact is made long enough so that it makes contact at each end with a metal layer, but design rule spacing is still maintained between the connections with the metal layer. The overlapping areas between the rectangular contact and the metal layers are asymmetrical. Alternatively, these overlapping areas are smaller than the design rule overlap requirements. In a second embodiment, a fuse element is constructed with a plurality of rectangular-shaped contacts. As a result, a current value that is significantly lower than conventional fuse current values, can be used to melt such a contact or blow the fuse.