Trench isolation structure

摘要

A trench isolation structure and method of forming the trench isolation structure and a MOSFET based thereon are disclosed. The method includes forming a generally T-shaped shallow trench isolation (STI) structure 35 having an overhang 34 and forming a gate stack 38. The method further includes forming source and drain recesses 40, which may be faceted recesses 40a, 40b, adjacent to the STI structure and the gate stack. The source and drain recesses are separated from the STI structure in the region under the overhang by substrate material 12a. Epitaxial source and drain regions 42 associated with the gate stack are formed by filling the source and drain recesses with stressor material, the substrate material 12a between the recesses and the STI structure acting as a seed layer for the stressor material.