science24.com - Numerical study of crucible bottom shape on the heat transport and fluid flow during the seeding process of oxide Czochralski crystal

Search for content and authors

Numerical study of crucible bottom shape on the heat transport and fluid flow during the seeding process of oxide Czochralski crystal

Mohammad Hossein Tavakoli ¹, Hermann Wilke ²

1. Physics Department, Bu-Ali Sina University, Mahdieh street, Hamedan 65174, Iran
2. Leibniz Institute for Crystal Growth (IKZ), Max-Born-Str 2, Berlin 12489, Germany

Abstract

For the seeding process of oxide Czochralski crystal growth, the influence of the crucible bottom shape on the heat generation, temperature and flow field of the system and the seed-melt interface shape have been studied numerically using the Finite Element Method. The configuration usually used in a real Czochralski crystal growth process consists of a crucible, active afterheater, induction coil with two parts, insulation, melt, gas and seed crystal. At first, the volumetric distribution of heat inside the metal crucible and afterheater inducted by the RF-coil was calculated. Using this heat generation in the crucible wall as a source the fluid flow and temperature field in the entire system as well as the seed-melt interface shape were determined. We have considered the two cases flat and rounded crucible bottom shape. It was observed that using a crucible with a rounded bottom has several advantages such as:

- The position of the maximum of heat generation at the crucible side wall moves upwards, compared to the flat bottom shape.

- The location of the temperature maximum at the crucible side wall rises and as a result the temperature gradient along the melt surface is increased.

- The streamlines of melt flow are parallel to the crucible bottom and have a curved shape similar to the rounded bottom shape. This way we do not have secondary flow usually observed in the crucible wall/bottom corner.

These important features lead to increasing thermal convection in the system and influence the velocity field in the melt and gas domain which helps preventing some serious growth problems such as spiral growth.

Legal notice

Legal notice:

Copyright (c) Pielaszek Research, all rights reserved.
The above materials, including auxiliary resources, are subject to Publisher's copyright and the Author(s) intellectual rights. Without limiting Author(s) rights under respective Copyright Transfer Agreement, no part of the above documents may be reproduced without the express written permission of Pielaszek Research, the Publisher. Express permission from the Author(s) is required to use the above materials for academic purposes, such as lectures or scientific presentations.
In every case, proper references including Author(s) name(s) and URL of this webpage: https://science24.com/paper/9477 must be provided.