Transistor structure with improved unclamped inductive switching immunity

A semiconductor transistor structure comprising:

• a substrate of a first conductivity type;
• an epitaxial layer adjacent to said substrate;
• a gate structure adjacent to and located above said epitaxial layer,
• a drain region of a second conductivity type within said epitaxial layer;
• a source region of said second conductivity type within said epitaxial layer;
• a body structure of said first conductivity type within said epitaxial layer at least partially formed under said gate structure and extending laterally under said source region;
• an electrically conductive trench-like feed-through element that passes through and contacts a first tub region of said first conductivity type formed under said source region and adjacent laterally to and in contact with said body structure;
• wherein said drain region comprises a first region accessible to a drain contact and spaced apart from said gate structure, and a second region less doped than said first region and located at least partially under said first region within said epitaxial layer, such that said second region extends to at least partially under said gate structure, wherein said second region is coarsely aligned with an edge of said gate structure;
• and
• a clamp region of a first conductivity type located under said first region such that said second region separates said first region and said clamp region.

A semiconductor device, comprising:

• an epitaxial layer grown over a doped substrate layer, both of a first conductivity type, said epitaxial layer comprising a source region and a drain region, both of a second conductivity type, said epitaxial layer further comprising a body structure of said first conductivity type;
• a gate structure above said epitaxial layer;
• an electrically conductive trench-like feed-through element that passes through said epitaxial layer and contacts said substrate layer and said source region;
• and
• a first tub region of said first conductivity type formed under said source region, and adjacent laterally to and in contact with said body structure, and wherein said first tub region is in contact with said trench-like feed-through element.