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US 5,314,841 AGranted
Method of forming a frontside contact to the silicon substrate of a SOI wafer
AssigneeInternational Business Machines Corporation
InventorsFrederick T. Brady, Nadim F. Haddad
Life of this patent
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Abstract
A method of having a frontside contact to a SOI wafer is described. Before any device processing steps a trench is etched through the SOI layers to the substrate. This trench is maintained during device processing and opened during source/drain implantation. At metallization an ohmic contact is made to the substrate.
Claims5
A method of fabricating a frontside contact to a silicon-on-insulator substrate, the substrate having a dopant type, comprising the steps of:
- defining a trench region on the surface of the SOI substrate before normal semiconductor device processing;
- etching the SOI layers down to the substrate;
- removing any trench defining material and continuing with normal device processing;
- opening the trench region during ion implantation of a dopant species of the same type as the substrate;
- covering the trench region during ion implantation of a dopant species of a different type as the substrate;
- and
- depositing metal in portions of the trench region during normal device processing to form an ohmic contact to the frontside of the SOI substrate.
4 more elements
In a silicon-on-insulator wafer, a method of forming a frontside contact comprising the steps of:
- a) defining a substrate contact region by use of photoresist
- b) etching a trench in the exposed contact regions;
- c) stripping the photoresist and resuming normal device processing;
- d) covering the substrate during implantation of a dopant of the opposite type from the substrate;
- e) opening the substrate trench region during implantation of similar dopant types to the substrate;
- and
- f) resume processing of the remaining fabrication steps to form a metal contact having ohmic contact to the silicon substrate via of the SOI wafer.
4 more elements
Dependencies are inferred from the claim text.