Single crystal silicon wafer having an epitaxial layer substantially free from 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
Epitaxial wafers comprising a single crystal silicon substrate comprising agglomerated vacancy defects and 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 intrinsic point defects on the substrate surface upon which the epitaxial layer is deposited.
Claims22
An epitaxial silicon wafer comprising:
- a single crystal silicon substrate comprising agglomerated vacancy defects and 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 having a radial width of at least about 40% of the length of the radius of the substrate;
- an epitaxial layer deposited upon a surface of the substrate, the epitaxial layer being substantially free of grown-in defects, wherein the epitaxial layer has a thickness of about 1 to about 15 microns.
An epitaxial silicon wafer comprising:
- a single crystal silicon substrate wafer comprising agglomerated vacancy defects, the wafer being 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 comprising agglomerated vacancy defects, the substrate being characterized in that it has 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 caused by agglomerated interstitial defects present at the substrate surface upon which the epitaxial layer is deposited.
Dependencies are inferred from the claim text.