Method and assembly for ohmic contact in thinned silicon carbide devices

A method of forming a semiconductor assembly, said method comprising:

• forming one or more electronic devices on a first surface of a semiconductor substrate formed of a silicon carbon (SiC) material and having a first thickness defined between the first surface and a second surface opposing the first surface;
• thinning the semiconductor substrate using a mechanical grinding process on a second surface of the substrate to a second thickness, the second thickness defined between the first surface and a third surface of the substrate formed by the mechanical grinding process;
• applying a metal film to the third surface;
• converting the metal film to a non-ohmic alloy layer on the third surface by heating to a first temperature range for a predetermined period of time;
• and
• annealing the non-ohmic alloy layer using localized heating of portions of the third surface by laser energy directed at the portions.

A silicon carbide semiconductor assembly comprising:

• a substrate layer formed of a first conductivity type silicon carbide semiconductor material, said substrate layer comprising a first surface, a second surface on an opposite side of said substrate layer from said first surface, and a first thickness of the substrate layer extending therebetween;
• one or more electronic devices formed on said first surface;
• and
• an ohmic layer of a second phase of a metal silicide formed on a third surface of said substrate layer, said third surface formed when said second surface is removed from said substrate layer leaving a second thickness of said substrate layer, said ohmic layer of metal silicide converted from a non-ohmic layer of first phase of metal silicide, said non-ohmic layer of metal silicide formed in a relatively low temperature alloy heating process from a layer of metal deposited onto said second surface, said ohmic layer of metal silicide converted from said non-ohmic layer of metal silicide using a relatively high temperature local heating source.