Memc Electronic Materials, Inc.

Charles C Yang

Gregory M Wilson

Jon A Rossi

A wafer is characterized in that the wafer has a non-uniform distribution of crystal lattice vacancies, wherein the concentration of crystal lattice vacancies in the bulk layer are greater than the concentration of crystal lattice vacancies in the front surface layer. In addition, the front surface of the wafer has an epitaxial layer, having a thickness of less than about 2.0 &#xe7;m, deposited thereon. A process comprises heating a surface of a wafer starting material to remove a silicon oxide layer from the surface and depositing an epitaxial layer onto the surface to form an epitaxial wafer. The epitaxial wafer is then heated to a soak temperature of at least about 1175C. while exposing the epitaxial layer to an oxidizing atmosphere comprising an oxidant, and the wafer is cooled at a rate of at least about 10C./sec.

Epitaxial silicon wafer with intrinsic gettering and a method for the preparation thereof

This invention is directed to a novel a single crystal silicon wafer. In one embodiment, this wafer comprises: (a) two major generally parallel surfaces (i.e., the front and back surfaces); (b) a central plane between and parallel to the front and back surfaces; (c) a front surface layer which comprises the region of the wafer extending a distance of at least about 10 &mgr;m from the front surface toward the central plane; and (d) a bulk layer which comprises the region of the wafer extending from the central plane to the front surface layer. This wafer is characterized in that the wafer has a non-uniform distribution of crystal lattice vacancies, wherein (a) the concentration of crystal lattice vacancies in the bulk layer are greater than the concentration of crystal lattice vacancies in the front surface layer, (b) the crystal lattice vacancies have a concentration profile in which the peak density of the crystal lattice vacancies is at or near the central plane, and (c) the concentration of crystal lattice vacancies generally decreases from the position of peak density toward the front surface of the wafer. In addition, the front surface of the wafer has an epitaxial layer deposited thereon. This epitaxial layer has a thickness of from about 0.1 to about 2.0 &mgr;m.

This invention is directed to a novel a single crystal silicon wafer. The wafer comprises: (a) two major generally parallel surfaces (ie., the front and back surfaces); (b) a central plane between and parallel to the front and back surfaces; (c) a front surface layer which comprises the region of the wafer extending a distance of at least about 10 &mgr;m from the front surface toward the central plane; and (d) a bulk layer which comprises the region of the wafer extending from the central plane to the front surface layer. This wafer is characterized in that the wafer has a non-uniform distribution of crystal lattice vacancies, wherein (a) the concentration of crystal lattice vacancies in the bulk layer are greater than the concentration of crystal lattice vacancies in the front surface layer, (b) the crystal lattice vacancies have a concentration profile in which the peak density of the crystal lattice vacancies is at or near the central plane, and (c) the concentration of crystal lattice vacancies generally decreases from the position of peak density toward the front surface of the wafer. In addition, the front surface of the wafer has an epitaxial layer deposited thereon. The epitaxial layer has an average light scattering event concentration of no greater than about 0.06/cm,as measured by a laser-based auto inspection tool configured to detect light scattering events corresponding to polystyrene spheres having diameters of no less than about 0.12 &mgr;m. The bulk layer comprises voids which are at least about 0.01 &mgr;m in their largest dimension.

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Gilbert, AZ, United States of America

Charles C Yang