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Laser Hydrogenation of Laser Doped and Grooved Structure
S. Wang, L. Mai, A. Ciesla, Z. Hameiri, C. Chan, B. Hallam, A. Sugianto, C.M. Chong, J. Ji, Z. Shi, S. Wenham
Czochralski (Cz), Adhesion, Plating, Laser Doping, Laser Damage
Wafer-Based Silicon Solar Cells and Materials Technology
Subtopic: Silicon Feedstock, Crystallisation and Wafering
Event: 32nd European Photovoltaic Solar Energy Conference and Exhibition
Session: 2CO.1.3
391 - 395
ISBN: 3-936338-41-8
Paper DOI: 10.4229/EUPVSEC20162016-2CO.1.3
0,00 EUR
Document(s): paper


Both Buried Contact Solar Cells (BCSC) and Laser Doped Selective Emitter (LDSE) solar cells have shown great success in large-scale manufacturing. Recent studies show that plated contacts can be more durable than screen-printed contacts. A new concept of laser doping with grooving in a simultaneous step is introduced to form narrow grooves with heavily doped walls with the metal contact subsequently formed by plating. This process capitalizes on the benefits of both BCSC and LDSE cells. The width of the groove is only about three to five microns. The narrow width and corresponding steep walls of the groove make it possible to deposit the antireflection coating (ARC) after the laser grooving process such that the groove walls remain uncovered to allow nucleation of subsequent metal plating. Formation of laser-induced defects is minimized because thermal expansion mismatch between the ARC and silicon is avoided during the laser doping process. This structure leads to greatly enhanced adhesion of the plated contact due to it being buried underneath the silicon (Si) surface. Although the laser doping and grooving process avoids thermal mismatch between SiNx and Si, crystallographic defects are formed during the laser grooving process. Laser-activated hydrogenation is used to passivate the laser-induced defects formed during the laser–doping and grooving process. Through this. excellent results have been achieved in terms of improved carrier lifetime and implied Voc values.