Effects of crystal-crucible iso-rotation and a balanced/unbalanced cusp magnetic field on the heat, flow, and oxygen transport in a Czochralski silicon melt

Thi Hoai Thu Nguyen, Jyh Chen Chen, Chieh Hu, Chun Hung Chen

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The effects of using a balanced/unbalanced cusp magnetic field (CMF) along with crystal-crucible counter-/iso-rotation on the heat, flow, and oxygen distributions during Czochralski (Cz) growth of an 8-inch silicon crystal are numerically investigated. One counter-rotation example is compared to iso-rotation cases. In both rotation modes, the vertical flow in the central melt region is strengthened while the buoyancy-driven melt flow is weakened under a cusp field. The CMF has a stronger effect on the oxygen content when there is a large difference in rotation rate between the crystal and the crucible (nS − nC). This is because a higher value of (nS − nC) induces stronger melt convection and hence, the Lorentz force has a more significant effect on a fast melt flow than a slow one. Although diffusion significantly influences oxygen transport in the melt at low crystal iso-rotation rates, different flow patterns and local melt velocities induced by different crystal iso-rotation speeds will modify the oxygen distribution. There is a slight change in the oxygen content at a low ingot iso-rotation rate with a CMF. In cases of iso-rotation, the radial oxygen content is enhanced more by an unbalanced CMF than a balanced one. Greater uniformity of the radial oxygen concentration is achieved applying iso-rotation with nS > nC under a CMF.

Original languageEnglish
Article number125373
JournalJournal of Crystal Growth
Volume531
DOIs
StatePublished - 1 Feb 2020

Keywords

  • A1. Computer simulation
  • A1. Convection
  • A1. Magnetic field
  • A1. Mass transfer
  • A2. Czochralski method

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