Coincident site lattice bi-crystals growth—Impurity segregation towards grain boundaries

Publication date: 15 April 2015
Source:Journal of Crystal Growth, Volume 416
Author(s): Antoine Autruffe , Lasse Vines , Lars Arnberg , Marisa Di Sabatino
Bi-crystal silicon ingots with coincident site lattice (CSL) grain boundaries (GB), namely Σ3, Σ9, Σ27a, have been grown in a small scale Bridgman type furnace at 3µm/s. Melts have been intentionally polluted with 25ppma of copper and indium. Segregation of these impurities towards the central grain boundaries has been assessed by secondary ion mass spectrometry (SIMS). Influence of topological imperfections and grain boundary nature has been investigated. While copper segregation towards Σ3 GB has not been detected, copper has been found to diffuse towards Σ9 and Σ27a GB, especially at steps and GB junctions. Indium segregation has not been detected at any GB. This indicates that slow-diffusing element segregation towards GB depends on the boundary nature, and/or the grains orientation.