Buried source-drain contact for integrated circuit transistor devices and method of making same

A method, comprising:

• providing a bulk substrate including a first semiconductor layer located between a base substrate layer and a second semiconductor layer;
• forming a trench in the bulk substrate, wherein the trench extends through the second semiconductor layer and into the first semiconductor layer;
• at least partially filling the trench with a metal material to form a source contact buried in the bulk substrate, but exposing a side wall of the bulk substrate;
• doping the exposed side wall of the bulk substrate to define a source region adjacent a channel region, wherein the source region and the channel region are located in the second semiconductor layer;
• providing a gate dielectric on top of the channel region;
• forming a gate electrode on the gate dielectric;
• and
• forming a conductive junction in the trench to electrically connect a top of the buried source contact to a side of the source region, the conductive junction provided at a same level as the second semiconductor layer.

A method, comprising:

• forming a trench in a bulk substrate comprising a semiconductor material, wherein the trench extends to a depth below a top portion of the bulk substrate;
• at least partially filling the trench with a metal material to form a source contact buried in the bulk substrate, but exposing a side wall of the bulk substrate;
• doping the exposed side wall of the bulk substrate to define a source region adjacent a channel region, wherein the source region and the channel region are located in a top portion of the bulk substrate;
• providing a gate dielectric on top of the channel region;
• forming a gate electrode on the gate dielectric;
• and
• forming a conductive junction in the trench to electrically connect a top of the buried source contact to a side of the source region, the conductive junction provided at a same level as the top portion of the bulk substrate.