An implantable expandable medical device in which selected regions of the device are in a martensite phase and selected regions are in an austenite phase. The system and method also includes a fuse banks for programming respective addresses of up to two defective columns that are to be repaired. A plurality of spaced mating posts project from the mating face of the housing. A deeper trench than the N+-type impurity implantation region is formed in the upper surface of the N\u2212-type silicon substrate.