Process of fabricating semiconductor devices with isolation and sinker regions containing trenches filled with conductive material
OwnerHamza Yilmazinventor
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Abstract
A semiconductor structure includes a trench formed in an epitaxial layer that overlies a semiconductor substrate, the sides of the trench being lined with an oxide layer. The trench is filled with a conductive material, e.g., a metal or heavily-doped polysilicon, and the conductive is in contact with the substrate or a doped region in the substrate or epitaxial layer. The structure expands far less horizontally than conventional diffusions and therefore allows a higher packing density of devices formed in the epitaxial layer. The structure may be used in place of conventional sinkers and isolation diffusions.
Claims4
A process of fabricating a semiconductor structure, said process comprising:
- providing a semiconductor substrate;
- growing an epitaxial layer on said substrate;
- forming a mask layer on a surface of said epitaxial layer;
- forming an opening in said mask layer;
- etching said epitaxial layer through said opening in said mask layer to form a trench;
- continuing said etching until a floor of said trench is located in said substrate;
- forming an oxide layer on a sidewall and floor of said trench;
- removing a first portion of said oxide layer from said floor of said trench while leaving a second portion of said oxide layer on said sidewall of said trench;
- depositing a layer of polysilicon layer into said trench, said polysilicon layer being doped with material of a first conductivity type;
- removing a portion of said polysilicon layer such that a top surface of said polysilicon layer is located at or below a top surface of said epitaxial layer;
- and
- forming a metal contact in electrical contact with said top surface of said polysilicon layer.
Dependencies are inferred from the claim text.