Silicon wafer and epitaxial silicon wafer
AssigneeSumco Corporation
InventorsKohtaroh KOGA, Yasuhito NARUSHIMA, Naoya NONAKA
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Abstract
A silicon wafer is provided in which a dopant is phosphorus, resistivity is 1.2 mΩ·cm or less, and carbon concentration is 3.5×1015 atoms/cm3 or more. The carbon concentration is decreased by 10% or more near a surface of the silicon wafer compared with a center-depth of the silicon wafer.
Claims45
An epitaxial wafer of 300 mm in diameter comprising:
- a silicon substrate having a resistivity of 1.2 mΩ-cm or less;
- an epitaxial layer on the silicon substrate;
- and
- a boundary between the epitaxial layer and the silicon substrate;
- wherein the silicon substrate has a carbon concentration of 3.5×1015 atoms/cm3 or more.
An epitaxial wafer of 300 mm in diameter comprising:
- a silicon substrate having a resistivity of 1.2 mΩ-cm or less, and a carbon concentration of 3.5×1015 atoms/cm3 or more at about center of the silicon substrate in a depth direction;
- an epitaxial layer on the silicon substrate;
- and
- a boundary between the epitaxial layer and the silicon substrate;
- wherein the silicon substrate further has a low carbon concentration layer near the boundary.
A silicon wafer having a diameter of 300 mm, a resistivity of 1.2 mΩ-cm or less, and a carbon concentration of 3.5×1015 atoms/cm3 or more at about center of the silicon wafer in a depth direction.
An epitaxial wafer of 300 mm in diameter comprising:
- a silicon substrate having a resistivity of 1.2 mΩ-cm or less;
- an epitaxial layer on top of the silicon substrate;
- and
- a boundary between the epitaxial layer and the silicon substrate;
- wherein
- a carbon concentration in the silicon substrate is 3.5×1015 atoms/cm3 or more, and
- the carbon concentration is decreased by 10% or more starting from a depth of 5 μm to 15 μm from the boundary.
A silicon wafer of 300 mm in diameter doped with phosphorus and having a resistivity of 1.2 mΩ-cm or less,
- the silicon wafer comprising a top surface and a bottom surface;
- wherein a carbon concentration in the silicon wafer is 3.5×1015 atoms/cm3 or more, and
- the carbon concentration is decreased by 10% or more starting from a depth of 5 μm to 15 μm from the top surface.
A method of making an epitaxial wafer of 300 mm in diameter comprising:
- adding phosphorus and carbon to a silicon melt in a crucible;
- placing the crucible in a furnace;
- rotationally pulling a single crystal from the silicon melt with a puller;
- cutting the single crystal into form at least one silicon wafer;
- and
- forming an epitaxial layer on a surface of the silicon wafer, wherein the silicon wafer has a carbon concentration of 3.5×1015 atoms/cm3 or more therein.
Dependencies are inferred from the claim text.