A wafer is diffused along opposite surfaces with bands of alternating conductivity type so that a band on one major surface is aligned with a band of an opposite conductivity type on the opposite major surface. Grooves are formed to separate bands along one major surface while grooves are formed at substantially right angles on the opposite major surface. The wafer may then be sub-divided along the grooves to form integrated rectifier units formed of unitary semiconductive elements. Contacts associated with one major surface may be utilized to provide a thermally conductive path to a thermally conductive, electrically insulative surface of a substrate. The contacts and a passivant associated with the semiconductive element together encapsulate the semiconductive element.