Abstract: A method of forming a self aligned guard ring surrounding a schottky barrier diode device without requiring an enlargement of the final schottky barrier device. The method involves creating an overhanging opening in a insulator layer overlying a semiconductor body to expose the schottky contact area on the surface of the semiconductor body, depositing a diffusion barrier material such as molybdenum in the opening, the deposit being of the same size as the smallest part of the overhanging opening so that a guard ring can be formed from a vapor by diffusion around the deposited barrier material.