Epitaxial silicon wafers substantially free of grown-in defects
AssigneeMEMC Electronic Materials, Inc.
InventorsLuciano Mule'Stagno, Lu Fei, Joseph C. Holzer, Harold W. Korb, Robert J. Falster
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Abstract
The present invention is directed to a set of epitaxial silicon wafers assembled in a wafer cassette, boat or other wafer carrier. Each wafer comprises a single crystal silicon substrate having an axially symmetric region in which silicon self-interstitials are the predominant intrinsic point defect and which is substantially free of agglomerated defects, and an epitaxial layer which is deposited upon a surface of the substrate and which is substantially free of grown-in defects caused by the presence of agglomerated silicon self-interstitial defects on the substrate surface upon which the epitaxial layer is deposited.
Claims35
A set of epitaxial silicon wafers assembled in a wafer cassette, boat or other wafer carrier, each of said wafers comprising:
- a single crystal silicon substrate having a central axis, a front surface and a back surface which are generally perpendicular to the central axis, a circumferential edge, and a radius extending from the central axis to the circumferential edge, the substrate comprising a first axially symmetric region in which silicon self-interstitials are the predominant intrinsic point defect and which is substantially free of agglomerated interstitial defects, the axially symmetric region extending radially inwardly from the circumferential edge of the substrate;
- and,
- an epitaxial layer deposited upon a surface of the substrate, the epitaxial layer being substantially free of grown-in defects.
A set of epitaxial silicon wafers assembled in a wafer cassette, boat or other wafer carrier, each of said wafers comprising:
- a single crystal silicon substrate wafer obtained from a single crystal silicon ingot prepared in accordance with the Czochralski method and having a nominal diameter of at least about 150 mm, the substrate having a central axis, a front surface and a back surface which are generally perpendicular to the central axis, a circumferential edge, and a radius extending from the central axis to the circumferential edge, the substrate being characterized in that it has a first axially symmetric region in which silicon self-interstitials are the predominant in trinsic point defect and which is substantially free of agglomerated interstitial defects, the axially symmetric region extending radially inwardly from the circumferential edge of the substrate;
- and,
- an epitaxial layer deposited upon a surface of the substrate, the epitaxial layer being substantially free of grown-in defects caused by agglomerated interstitial defects present at the substrate surface upon which the epitaxial layer is deposed.
Dependencies are inferred from the claim text.