BUTTED SOI JUNCTION ISOLATION STRUCTURES AND DEVICES AND METHOD OF FABRICATION

摘要

A structure, a FET, a method of making the structure and of making the FET. The structure including: a silicon layer (105; Fig. 5) on a buried oxide (BOX) layer (115) of a silicon-on-insulator substrate (100); a trench in the silicon layer extending from a top surface of the silicon layer into the silicon layer, the trench not extending to the BOX layer (160, 165, and 170), a doped region (155) in the silicon layer between and abutting the BOX layer and a bottom of the trench, the first doped region doped to a first dopant concentration; a first epitaxial layer (160), doped to a second dopant concentration, in a bottom of the trench; a second epitaxial layer (165), doped to a third dopant concentration, on the first epitaxial layer in the trench; and wherein the third dopant concentration is greater than the first and second dopant concentrations and the first dopant concentration is greater than the second dopant concentration.