Epitaxial silicon wafer free from autodoping and backside halo and a method and apparatus for the preparation thereof
First Claim
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1. A single crystal silicon wafer, the single crystal silicon wafer comprising:
- a silicon wafer 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 of the wafer, the back surface being free of an oxide seal and substantially free of a chemical vapor deposition process induced halo, the silicon wafer substrate comprising P-type or N-type dopant atoms; and
an epitaxial silicon layer on the front surface of the silicon wafer substrate characterized by an axially symmetric region extending radially outwardly from the central axis toward the circumferential edge wherein the resistivity is substantially uniform, the radius of the axially symmetric region being at least about 80% of the length of the radius of the substrate, the epitaxial silicon layer comprising P-type or N-type dopant atoms.
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Abstract
A single crystal silicon wafer with a back surface free of an oxide seal and substantially free of a chemical vapor deposition process induced halo and an epitaxial silicon layer on the front surface, the epitaxial layer is characterized by an axially symmetric region extending radially outwardly from the central axis of the wafer toward the circumferential edge of the wafer having a substantially uniform resistivity, the radius of the axially symmetric region being at least about 80% of the length of the radius of the wafer.
72 Citations
87 Claims
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1. A single crystal silicon wafer, the single crystal silicon wafer comprising:
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a silicon wafer 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 of the wafer, the back surface being free of an oxide seal and substantially free of a chemical vapor deposition process induced halo, the silicon wafer substrate comprising P-type or N-type dopant atoms; and
an epitaxial silicon layer on the front surface of the silicon wafer substrate characterized by an axially symmetric region extending radially outwardly from the central axis toward the circumferential edge wherein the resistivity is substantially uniform, the radius of the axially symmetric region being at least about 80% of the length of the radius of the substrate, the epitaxial silicon layer comprising P-type or N-type dopant atoms. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A process for growing an epitaxial silicon layer on a silicon wafer substrate in a chemical vapor deposition chamber, the silicon wafer substrate having a front surface and a back surface, the process comprising:
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contacting the front surface of the silicon wafer substrate and substantially the entire back surface of the silicon wafer substrate with a cleaning gas to remove an oxide layer from the front surface and the back surface of the silicon wafer substrate;
growing an epitaxial silicon layer on the front surface of the silicon wafer substrate after the oxide layer has been removed; and
introducing a purge gas into the chemical vapor deposition chamber during the growth of the epitaxial silicon layer to reduce the number of out-diffused dopant atoms from the back surface of the silicon wafer substrate incorporated in the epitaxial silicon layer. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
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55. An apparatus for use in a chemical vapor deposition process wherein an epitaxial silicon layer is grown on a silicon wafer substrate, the apparatus comprising:
a susceptor sized and configured for supporting the silicon wafer thereon, the susceptor having a surface having a density of openings between about 0.2 openings/cm2 and about 4 openings/cm2, the surface being in a generally parallel opposed relationship with the silicon wafer to permit fluid flow therethrough for fluid contact with the back surface of the silicon wafer. - View Dependent Claims (56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67)
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68. An apparatus for use in an epitaxial deposition process wherein an epitaxial silicon layer is grown on a silicon wafer substrate, the silicon wafer substrate having a front surface and a back surface, the apparatus comprising:
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a chamber;
a wafer support device for supporting the silicon wafer substrate and for permitting fluid contact with the front surface of the silicon wafer substrate and substantially the entire back surface of the silicon wafer substrate;
rotatable means for supporting the wafer support device and silicon wafer substrate;
a heating element;
a gas inlet for allowing cleaning gas, source gas and purge gas to enter the apparatus; and
a gas outlet for allowing cleaning gas, source gas and purge gas to exit the apparatus. - View Dependent Claims (69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87)
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Specification