Silicon wafer having good intrinsic getterability and method for its production

US7964275B2 · kind B2 · utility

Assignee

• Siltronic AG · DE

Inventors

• Timo Müller · Helsinki, FI
• Martin Weber · Borgo San Lazzaro, DE
• Gudrun Kissinger · Lebus, DE

Key dates

• Filing date: Oct 2, 2007
• Grant date: Jun 21, 2011
• Expiry date: Jan 15, 2030

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/26
• WIPO field: Surface technology, coating
• WIPO sector: Chemistry

Abstract

Silicon wafers in the entire volume of which crystal lattice vacancies are the prevalent point defect type, have a rotationally symmetric region whose width is at least 80% of the wafer radius, crystal lattice vacancy agglomerates of at least 30 nm in a density ≦6·103 cm−3, crystal lattice vacancy agglomerates of from 10 nm to 30 nm in a density of 1·105 cm−3 to 3·107 cm−3, OSF seeds in a density of 0 to 10 cm−2, and an average bulk BMD density of 5·108 cm−3 to 5·109 cm−3, which varies at most by a factor of 10 radially over the entire silicon wafer, and a BMD-free layer on the front side, wherein the first BMD is found at a depth of at least 5 μm and on average at a depth of at least 8 μm.