Processing of high efficiency silicon solar cells
No Thumbnail Available
URL
Journal Title
Journal ISSN
Volume Title
Doctoral thesis (monograph)
Checking the digitized thesis and permission for publishing
Instructions for the author
Instructions for the author
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.
Authors
Date
2001-11-09
Major/Subject
Mcode
Degree programme
Language
en
Pages
106
Series
Reports in electron physics, 2001/28
Abstract
Fabrication technology of high efficiency silicon solar cells has been studied in this work. Process development work has been carried out since 1997 within a project "Development of high-efficiency low-cost silicon solar cells", which was funded by TEKES, Fortum Advanced Energy Systems and Okmetic Ltd. Co - operation with photovoltaic research group of Fortum Surface Chemistry has been very close during the project. Target of this project is to demonstrate by low cost processing technologies, the feasibility of the fabrication of solar cells with a conversion efficiency as high as possible. Three different solar cell configurations and their processing technologies are discussed in this content. The solar cells processed by industrially feasible methods on the low cost multicrystalline silicon wafers are the main focus of this work. Solar cells made of single crystalline silicon are studied in order to reveal the capability of the fabrication process in scope of the conversion efficiency. The third cell technology is the devices made by Rapid Thermal Processing of silicon wafers. That topic has been studied because of its possible potential for excellent manufacturability. Processing of the solar cells has been carried out in the clean room facilities of Microelectronics Center at HUT. In addition to device processing, a special issue in this project has been characterization of metallic impurities and defects in multicrystalline silicon material. Minimization of unwanted impurities and defects as well as understanding their interactions is necessary when processing high performance devices. Process induced contamination sources has been charted by μPCD (microwave Photoconductive Decay) and SPV (Surface Photovoltage) measurements. Other special issues in this thesis are investigation of passivation properties of PECVD grown Si3N4 films, optimization of emitter diffusion and Cr/Cu front contact metallization. During three years, several hundreds of single and multicrystalline silicon wafers have been processed to solar cells. Best conversion efficiencies were 15,1 % (mc-Si), 16,4 % (c-Si) and 14,5 % (RTP mc-Si).Description
Keywords
solar cells, multicrystalline silicon, silicon processing, lifetime