Isolation structures for integrated circuits
AssigneeAdvanced Analogic Technologies, Inc.
InventorsRichard K. Williams, Donald Ray Disney, Wai Tien Chan
Life of this patent
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Abstract
A variety of isolation structures for semiconductor substrates include a trench formed in the substrate that is filled with a dielectric material or filled with a conductive material and lined with a dielectric layer along the walls of the trench. The trench may be used in combination with doped sidewall isolation regions. Both the trench and the sidewall isolation regions may be annular and enclose an isolated pocket of the substrate. The isolation structures are formed by modular implant and etch processes that do not include significant thermal processing or diffusion of dopants so that the resulting structures are compact and may be tightly packed in the surface of the substrate.
Claims5
An isolation structure formed in a semiconductor substrate of a first conductivity type, the substrate not comprising an epitaxial layer, the structure comprising:
- a floor isolation region of a second conductivity type opposite to the first conductivity type submerged in the substrate;
- an annular sidewall region of the second conductivity type extending downward from a surface of the substrate at least to the floor isolation region such that the annular sidewall region overlaps the floor isolation region, wherein the floor isolation region and annular sidewall region together enclose an isolated pocket of the substrate;
- and
- an annular dielectric-filled trench extending downward from the surface of the substrate, the annular dielectric-filled trench abutting the annular sidewall region.
Dependencies are inferred from the claim text.