Characterization of the loss of the dislocation-free growth during Czochralski silicon pulling

• Published in: Journal of crystal growth Vol. 458; pp. 120 - 128
• Main Authors: Lanterne, Adeline, Gaspar, Guilherme, Hu, Yu, Øvrelid, Eivind, Di Sabatino, Marisa
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.01.2017; Elsevier BV
• Subjects: A1. Dislocations; A2. Czochralski method; B2. Semiconducting silicon; B3. Solar cells; Bubbles; Cross-sections; Crystal dislocations; Crystal growth; Crystal pulling; Dislocations; Perturbation; Photovoltaic cells; Silicon; Solidification; A1. Dislocations; A2. Czochralski method; B3. Solar cells; B2. Semiconducting silicon
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2016.10.077

The loss of the dislocation-free growth (structure loss) during Czochralski (Cz) silicon pulling can have a strong negative impact on the production yield of the Cz photovoltaic industry. As almost no publication has been dedicated to this phenomenon in the past, this paper aims at investigate in detail the loss of the dislocation-free growth and its origin by characterizing an industrial-scale n-type Cz silicon ingot exhibiting such issue. After the occurrence of a perturbation, generation and propagation of slip dislocations in the already grown crystal have been observed. These dislocations, generated over the whole ingot cross-section, propagate with the solidification front during further growth. Additional small perturbations seem then to be responsible for their multiplication together with the transition to a multicrystalline structure. Investigations were conducted to find the perturbation causing the structure loss in the ingot. A pinhole, small gas bubble of 0.5mm diameter, was identified as the main cause for the generation of dislocations. •Characterization of the generation and propagation of dislocations during Cz silicon pulling.•Delineation of the transition from a dislocation-free growth to a growth with dislocations.•Observation of dislocations multiplication and of new grains nucleation.•A gas bubble seems to be the cause of the structure loss.