# US 2010/0164071 A1 · Silicon wafer and method for producing the same

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- Number: US 2010/0164071 A1
- Document ID: US20100164071A1
- Status: Published application
- Kind: A1
- Application number: 12/653,651
- Filed: 2009-12-16
- Published: 2010-07-01
- Earliest claimed: 2008-12-26
- Assignees: Siltronic AG
- Inventors: Katsuhiko Nakai; Atsushi Ikari; Masamichi Ohkubo
- Web page: https://patentgrep.com/patent/US20100164071A1

## CPC

- C30B 15/00: Single-crystal growth by pulling from a melt, e.g. Czochralski method (under a protective fluid C30B27/00)
- C30B 29/06: Silicon
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR

## Abstract

Silicon wafers having excellent voltage resistance characteristics of an oxide film and high C-mode characteristics are derived from single crystal silicon ingots doped with nitrogen and hydrogen, characterized in that a plurality of voids constituting a bubble-like void aggregates are present ≧50% relative to total voids; a V1 region having a void density of over 2×104/cm3 and below 1×105/cm3 is ≦20% of the total area of wafer; a V2 region having a void density of 5×102 to 2×104/cm3 occupies ≧80% of the total area of the wafer; and bulk microdefect density is ≧5×108/cm3.

## Claims

### Claim 1

A silicon wafer doped with nitrogen and hydrogen, comprising:
a plurality of voids constituting bubble-like void aggregates which are present in an amount ≧ to 50% of total void number;
a V1 region having a void density of over 2×104/cm3 and below 1×105/cm3 which occupies ≦ to 20% of the total area of the silicon wafer;
a V2 region having a void density of 5×102 to 2×104/cm3 which occupies to 80% of the total area of the silicon wafer; and
a bulk micro defect density ≧5×108/cm3.

### Claim 2 (depends on 1)

A method for producing a silicon wafer of claim 1, comprising obtaining a silicon wafer from a silicon crystal pulled by a method comprising:
setting a nitrogen concentration in the silicon crystal from 3×1013 to 3×1015 atoms/cm3;
setting a pressure of the atmosphere inside a crystal pulling furnace from 40 to 250 mbar;
introducing hydrogen in an amount of 1 to 3.8% by volume into the atmosphere;
establishing a temperature gradient in a longitudinal direction of the silicon crystal over the range of 1100° to 1200° C. during pulling of the silicon crystal to ≧ to 3.5° C./mm; and
controlling an upper limit of pulling speed such that a V1 region having a void density of over 2×104/cm3 and below 1×105/cm3 is ≦20% of the total area of the silicon wafer, and controlling a lower limit of pulling speed such that a V2 region having a void density of 5×102 to 2×104/cm3≧80% of the total area of said silicon wafer.

### Claim 3 (depends on 2)

The method of claim 2, wherein the oxygen concentration in the silicon crystal is set to be ≦ to 7×1017 atoms/cm3.