A small diameter Bridgman equipment was used to grow multi-crystalline silicon of 3 cm diameter in a graphite crucible. The purpose of the work is to study the influence of process parameters on the resistivity and lifetime profiles and to understand the relation between melt convection and impurity distribution.

   According to the literature [1], a convective dissolution rate of a crucible leads to a higher impurity concentration in the melt. In the studied crystals a very high neutral impurity (C and O) concentration has been found. These impurities have largely entered the molten silicon through the liquid phase diffusion, aided by convective transport. Therefore the carbon concentration in the melt is strongly related with the time duration in which the silicon was in the molten phase. In order to study the influence of the carbon concentration on the resistivity distribution, first two experiments were performed: one with a shorter time in molten phase (fig.1.a) – probe A– and one with a longer time in molten phase (fig.1c) – probe B. It was observed that the resistivity pattern changed from a w-shape in radial direction for A (fig.1.b) to a v-shape for B (fig1.d). In the paper this behaviour in relation with the interface shape, melt convection and mobility limitation through scattering on neutral impurity centres (C and O) [2] will be explained.  

   Furthermore, we analyse the incorporation of impurities, their distribution and precipitation in relation with the multi-crystalline growth, through the lifetime and resistivity scans for other samples grown at different process parameters.

Figure1. Probe A:(a)Optical scan; (b)Resistivity scan. Probe B:(c)Optical scan; (d)Resistivity scan

[1] A. Popescu, D. Vizman - International Journal of Heat and Mass Transfer 54 (2011), 5540-5544

[2] P. S. Kireev, Semiconductor Physics, Mir Publishers 1978.

• 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/29791 must be provided.

1. Numerical study of the influence of the melt rotation on the impurities diffusion in a directional solidification process of multicrystalline silicon
2. Effects of Crucible Coating on the Quality of Multi-crystalline Silicon Grown by a Bridgman Technique
3. Model experiment on a special type of electromagnetical stirring in a GaInSn melt