Low resistance and inductance backside through vias and methods of fabricating same

A structure, comprising:

• a dielectric isolation in a substrate, said substrate having a frontside and an opposing backside;
• a first dielectric layer on said frontside of said substrate;
• and
• an electrically conductive through via extending through said first dielectric layer, said dielectric isolation and said substrate exposed on said backside of said substrate.

A method for forming a contact, comprising:

• forming a first dielectric layer on a frontside of a substrate, said substrate having a backside opposing said frontside;
• forming an electrically conductive first stud contact in said first dielectric layer, said first stud contact extending through said first dielectric layer to said frontside of said substrate;
• thinning said substrate from said backside of said substrate to form a new backside of said substrate;
• forming a trench in said substrate, said trench extending from said new backside of said substrate to said first dielectric layer, a bottom surface of said first stud contact exposed in said trench;
• and
• forming a conformal electrically conductive layer on said new backside of said substrate, sidewalls of said trench, exposed surfaces of said first dielectric layer and exposed surfaces of said first stud contacts, said conductive layer not thick enough to completely fill said trench.

A structure, comprising:

• a first dielectric layer on a frontside of a substrate, said substrate having a backside opposing said frontside;
• an electrically conductive first stud contact in said first dielectric layer, said first stud contact extending through said first dielectric layer to said frontside of said substrate;
• a trench in said substrate, said trench extending from said backside of said substrate to said first dielectric layer, a bottom surface of said first stud contact exposed in said trench;
• and
• a conformal electrically conductive layer over sidewalls of said trench, and on exposed surfaces of said first dielectric layer and exposed surfaces of said first stud contacts, said conductive layer not thick enough to completely fill said trench.

A method for forming a contact, comprising:

• performing a first ion implantation into a region of a frontside of substrate to form a first doped region in said substrate, said substrate having a backside opposing said frontside;
• growing an epitaxial layer on said frontside of said substrate;
• performing a second ion implantation into a region of a said epitaxial layer to form a second doped region in said epitaxial later, said second doped region aligned over at least a portion of said first doped region;
• and
• heating said substrate and epitaxial layer in order to convert said first and second doped regions into a continuous diffused through via extending from a top surface of said epitaxial layer into said substrate.

A method for forming a contact, comprising:

• forming a dielectric isolation in an upper substrate, a bottom surface of said upper substrate bonded to a top surface of a lower substrate, said lower substrate doped to a first concentration and said upper substrate doped to a second concentration, said second concentration greater than said first concentration;
• forming a first dielectric layer on a top surface of said upper substrate;
• forming a trench in said first dielectric layer, said trench aligned over and within a perimeter of said dielectric isolation and extending to said dielectric isolation;
• extending said trench formed in said first dielectric layer through said dielectric isolation and into and through said upper substrate to or into said lower substrate a distance less than a first thickness of said lower substrate;
• filling said trench and co-planarizing a top surface of said trench with a top surface of said first dielectric layer to form an electrically conductive through via;
• and
• thinning said lower substrate from a bottom surface of said substrate.

A structure, comprising:

• a dielectric isolation in an upper substrate, a bottom surface of said upper substrate bonded to a top surface of a lower substrate, said lower substrate doped to a first concentration and said upper substrate doped to a second concentration, said second concentration greater than said first concentration;
• a first dielectric layer on a top surface of said upper substrate;
• and
• an electrically conductive through via extending through said first dielectric layer, said trench isolation and said upper substrate to or into said lower substrate a distance less than a first thickness of said lower substrate.