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US 10,483,128 B2Granted
Epitaxially coated semiconductor wafer, and method for producing an epitaxially coated semiconductor wafer
AssigneeSiltronic AG
InventorsTimo Mueller, Michael Gehmlich, Frank Faller
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Abstract
Epitaxial wafers with a high concentration of BMD nuclei or developed BMDs just below a denuded zone, and having low surface roughness, are produced by forming an oxynitride layer on a purposefully oxidized epitaxial layer by a short RTA treatment in a nitriding atmosphere, removing the oxynitride layer, and then polishing the epitaxial surface.
Claims5
An epitaxially coated semiconductor wafer, comprising:
- a substrate wafer comprising monocrystalline silicon having a front side, rear side, a center, and a periphery;
- an epitaxial layer comprising silicon and having a polished surface on the front side of the substrate wafer, wherein the polished surface has an RMS roughness of not more than 0.055 nm in a measurement window having dimensions of 10 μm×10 μm;
- a denuded zone extending from the polished surface of the epitaxial layer to the rear side of the substrate wafer as far as a depth which, between the center and the periphery of the semiconductor wafer, is not less than 6 μm and not more than 14 μm, and
- a region adjoining the denuded zone and having BMD nuclei which can develop into BMDs by heat treatment, with a peak density of BMD nuclei of not less than 3.5×109 cm−3 at a distance of not more than 70 μm from the polished surface of the epitaxial layer.
1 more element
Dependencies are inferred from the claim text.