Title:	Very High Deposition Rate µc-Si:H Absorber Layer Deposition Using a Plasma Excitation Frequency of 140 MHz in Combination with High Process Pressures
Author(s):	C. Strobel, U. Merkel, B. Leszczynska, S. Leszczynski, J. Kuske, M. Albert, J.W. Bartha
Keywords:	PECVD, Solar Cell, High Rate, Microcrystalline Silicon, Very High Frequency
Topic:	THIN FILM SOLAR CELLS
Subtopic:	Silicon-based Thin Film Solar Cells
Event:	28th European Photovoltaic Solar Energy Conference and Exhibition
Session:	3CV.1.52
Pages:	2573 - 2579
ISBN:	3-936338-33-7
Paper DOI:	10.4229/28thEUPVSEC2013-3CV.1.52
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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The cost reduction of silicon based thin-film solar cells is of major importance in terms of the competitiveness of the technology. One major cost factor is the absorber layer deposition of the microcrystalline silicon (μc-Si:H) bottom cell of tandem devices. In this work results of the ultra fast μc-Si:H absorber layer deposition are described. To achieve the high deposition rates a plasma regime which combines high pressures and high power levels at an electrode distance of 10 mm and at a plasma excitation frequency of 140 MHz is used. At the beginning a μc-Si:H p-i-n reference process at moderate i-layer deposition rates (0.8 nm/s) was developed. After several optimization steps an efficiency of 8.3 % could be achieved (0.8 nm/s). In the next step the deposition rate of the absorber was increased up to 5 nm/s. Promising i-layer material with rates up to about 2.1 nm/s was incorporated into complete μc-Si:H p-i-n solar cells. A slight decrease of the solar cell parameters , FF, Uoc and Jsc was observed with increasing absorber deposition rate. Finally, an initial efficiency of 6.9 % could be achieved at an absorber layer deposition rate of 2.1 nm/s.