Method of forming electrode/wiring layer

A method of forming an electrode layer on a silicon substrate having a semiconductor region therein comprising the steps of:

• forming an insulating structure on the silicon substrate having a semiconductor region therein, said insulating member having a recess which extends from the surface of said semiconductor region to the exterior surface of said insulating structure and exposes a surface of said semiconductor region;
• forming a polycrystalline silicon body within said recess of said insulating structure, said polycrystalline silicon body filling only said recess;
• forming an aluminum layer to cover the entire polycrystalline silicon body and a surface of said insulating structure surrounding said polycrystalline silicon body, said aluminum layer being sufficiently large relative to the polycrystalline silicon body to allow said polycrystalline silicon body to convert completely into a silicon aluminum alloy during a heating process;
• and
• converting through a heating process substantially all of the polycrystalline silicon in said polycrystalline silicon body and the aluminum in the portion of the aluminum layer adjacent to said polycrystalline silicon body into an alloy of aluminum and silicon to form an electrode layer establishing a good electrical contact with the semiconductor region, the electrode layer comprising the alloy formed in said recess.