Ultra Thin Channel (UTC) MOSFET Structure Formed on BOX Regions Having Different Depths and Different Thicknesses Beneath the UTC and SourceDrain Regions and Method of Manufacture Thereof

摘要

A MOSFET structure includes a planar semiconductor substrate, a gate dielectric and a gate. A UT SOI channel extends to a first depth below the top surface of the substrate and is self-aligned to and is laterally coextensive with the gate. Source-drain regions, extend to a second depth greater than the first depth below the top surface, and are self-aligned to the UT channel region. A BOX 1 region extends across the entire structure, and vertically from the second depth to a third depth below the top surface. An upper portion of a BOX 2 region under the UT channel region is self-aligned to and is laterally coextensive with the gate, and extends vertically from the first depth to a third depth below the top surface, and where the third depth is greater than the second depth.