Body contact SOI transistor structure and method of making

A method of making a body-contact SOI transistor structure on a silicon-on-insulator (SOI) substrate, the SOI substrate including upper silicon on an insulator layer on bottom silicon, the method comprising:

• forming an opening through the upper silicon and the insulator layer, the opening exposing the bottom silicon;
• laterally etching the insulator layer underneath the upper silicon through the opening to create recessed regions in the opening underneath the upper silicon;
• filling the recessed regions with a polysilicon layer such that the polysilicon layer connects the upper silicon and the bottom silicon;
• filling the opening with an insulating dielectric layer;
• forming a gate stack over the SOI substrate, the gate stack having a first portion covering the opening and a second portion extending from the first portion and covering an area of the upper silicon across a middle portion of an active region of the body-contact SOI transistor;
• and
• forming source/drain junctions of the body-contact SOI transistor structure on opposite sides of the gate stack using self-aligned processes such that one of the source/drain junctions is on a first side of the opening while the other one of the source/drain junctions is on a second side of the opening opposite to the first side of the opening.