Method of passivating pn-junction in a semiconductor device

Abstract

Abstract The surface termination of a p-n junction of a semiconductor device is passivated with semi-insulating material which is deposited on a thin layer of insulating material formed at the bared semiconductor surface by a chemical conversion treatment at a temperature above room temperature. The layer may be formed by oxidizing the semiconductor material of the body for example in dry oxygen between 300° C. and 500° C. or in an oxidizing liquid containing for example hydrogen peroxide or nitric acid at for example 80° C. The layer is sufficiently thin to permit conduction (e.g. by tunnelling) between the semi-insulating material and the surface but thick enough to reduce said conduction so that when the junction is reverse-biased leakage current flows further along the semi-insulating material before flowing out to the surface across the layer. This increases the spread of the junction depletion layer along the surface thereby permitting a high breakdown voltage even with a high resistivity for the material. The thin layer can also act as a barrier against gettering of lifetime-killers (e.g. gold) from the semiconductor body by the semi-insulating material. The semi-insulating material may be based on amorphous or polycrystalline silicon or a chalcogenide.

Inventors

• 👤 Stephen W. Byatt

Bibliographic Details