Contact isolation scheme for thin buried oxide substrate devices

摘要

A method of forming a semiconductor-on-insulator (SOI) device includes defining a shallow trench isolation (STI) structure in an SOI substrate, the SOI substrate including a bulk layer, a buried insulator (BOX) layer over the bulk layer, and an SOI layer over the BOX layer; forming a doped region in a portion of the bulk layer corresponding to a lower location of the STI structure, the doped region extending laterally into the bulk layer beneath the BOX layer; selectively etching the doped region of the bulk layer with respect to undoped regions of the bulk layer such that the lower location of the STI structure undercuts the BOX layer; and filling the STI structure with an insulator fill material.

主权项

1. A method of forming a semiconductor-on-insulator (SOI) device, the method comprising:
defining a shallow trench isolation (STI) structure in an SOI substrate, the SOI substrate including a bulk layer, a buried insulator (BOX) layer over the bulk layer, and an SOI layer over the BOX layer; forming a doped region in a portion of the bulk layer corresponding to a lower location of the STI structure, the doped region extending laterally into the bulk layer beneath the BOX layer, wherein forming the doped region further comprises: forming a dopant source layer within the STI structure and on an exposed top surface of the bulk layer; and annealing to out-diffuse dopant atoms from the dopant source layer and define the doped region; selectively etching the doped region of the bulk layer with respect to undoped regions of the bulk layer such that the lower location of the STI structure undercuts the BOX layer; and filling the STI structure with an insulator fill material.