Title:	Welding of Monocrystalline Silicon by Various Laser Beam Geometries
Author(s):	M.T. Hessmann, T. Kunz, K. Cvecek, A. Bochmann, S. Christiansen, R. Auer, C.J. Brabec
Keywords:	Laser Processing, EBSD, Crystalline Silicon Thin-Films, Micro-Raman
Topic:	Thin Film Solar Cells
Subtopic:	Thin Film Crystalline Silicon Solar Cells
Event:	27th European Photovoltaic Solar Energy Conference and Exhibition
Session:	3CV.2.29
Pages:	2450 - 2452
ISBN:	3-936338-28-0
Paper DOI:	10.4229/27thEUPVSEC2012-3CV.2.29
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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Silicon thin film foils, which are welded together by laser offer a huge opportunity to use the high quality of float-zone grown silicon for high performance solar cells on a large scale. By this the area restriction of ingot based monocrystalline silicon wafer could be overcome. We present the further progress of welding 50 μm thin silicon films by comparing spot welding with continuous feed speed and using a laser line focus for welding. The successful welding of (100) silicon thin film foils is for both welding techniques demonstrated and analyzed by micro-Raman spectroscopy as well as Electron backscatter diffraction (EBSD). Both laser techniques cause newly formed grains and grain boundaries within the laser irradiated area in the silicon material. The internal stress measurements reveal compressive and tensile stress in the range of -147.5 MPa to 115.0 MPa.