ISOLATION STRUCTURE FOR IC WITH EPI REGIONS SHARING THE SAME TANK

摘要

An ESD cell includes an n+ buried layer (NBL) within a p-epi layer on a substrate. An outer deep trench isolation ring (outer DT ring) includes dielectric sidewalls having a deep n-type diffusion (DEEPN diffusion) ring (DEEPN ring) contacting the dielectric sidewall extending downward to the NBL. The DEEPN ring defines an enclosed p-epi region. A plurality of inner DT structures are within the enclosed p-epi region having dielectric sidewalls and DEEPN diffusions contacting the dielectric sidewalls extending downward from the topside surface to the NBL. The inner DT structures have a sufficiently small spacing with one another so that adjacent DEEPN diffusion regions overlap to form continuous wall of n-type material extending from a first side to a second side of the outer DT ring dividing the enclosed p-epi region into a first and second p-epi region. The first and second p-epi region are connected by the NBL.

主权项

1. An integrated circuit (IC), comprising:
a substrate having a p-type epitaxial (p-epi) layer thereon; an n+ buried layer (NBL) within said p-epi layer which defines a buried portion of said p-epi layer (buried p-epi layer) below said NBL; an outer deep trench isolation ring (outer DT ring) comprising at least a dielectric sidewall having a deep n-type diffusion (DEEPN diffusion) configured in a ring (DEEPN ring) in said p-epi layer layer contacting said dielectric sidewall extending downward from a topside surface of said p-epi layer to said NBL, said DEEPN ring enclosing a portion of said p-epi layer to define an enclosed p-epi region within, and a plurality of inner DT structures within said enclosed p-epi region each comprising at least a dielectric sidewalls having said DEEPN diffusion contacting said dielectric sidewalls and extending downward from said topside surface to said NBL, wherein said plurality of inner DT structures have a sufficiently small inner DT structure spacing so that adjacent ones of said DEEPN diffusion regions overlap to form continuous wall of n-type material which extends from a first side to a second side of said outer DT ring to divide said enclosed p-epi region into a first p-epi region and a second p-epi region, wherein said NBL in said first p-epi region connects to said NBL in said second p-epi region.