ELECTROMIGRATION-PROGRAMMABLE SEMICONDUCTOR DEVICE WITH BIDIRECTIONAL RESISTANCE CHANGE

An electromigration-programmable semiconductor device may be programmed to increase the resistance or to decrease the resistance by selecting the amount of current passed through the electromigration-programmable semiconductor device. The electromigration-programmable semiconductor device comprises an anode, a cathode, and a link, each having a semiconductor portion and a metal semiconductor alloy portion. The metal semiconductor alloy portion of the link comprises two disjoined sub-portions with a gap therebetween. A low programming current fills the gap by electromigrating a small amount of metal semiconductor alloy from the cathode, A high programming current forms a large metal-semiconductor-alloy-deleted area in the cathode to increase the resistance. A tri-state programming is achieved by selecting the programming current level.