Methods for producing low oxygen silicon ingots
US9951440B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 22, 2014 |
| Grant date | Apr 24, 2018 |
| Priority date | — |
| Expiry date | May 22, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D62/834
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An method for producing a silicon ingot includes melting polycrystalline silicon in a crucible enclosed in a vacuum chamber to form a melt, generating a cusped magnetic field within the vacuum chamber, dipping a seed crystal into the melt, withdrawing the seed crystal from the melt to pull a single crystal that forms the silicon ingot, wherein the silicon ingot has a diameter greater than about 150 millimeters (mm), and simultaneously regulating a plurality of process parameters such that the silicon ingot has an oxygen concentration less than about 5 parts per million atoms (ppma). The plurality of process parameters include a wall temperature of the crucible, a transport of silicon monoxide (SiO) from the crucible to the single crystal, and an evaporation rate of SiO from the melt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.