Title:	Recent Development of Low Temperature Plasma Enhanced CVD of Transparent Conducting Oxide in Photovoltaic Applications
Author(s):	H. Chandra, M. George, P. Morse, J. Madocks
Keywords:	PECVD, Transparent Conducting Oxides (TCO), Tin Oxide
Topic:	Thin Films
Subtopic:	Amorphous and Microcrystalline Silicon
Event:	23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain
Session:	3AV.2.42
Pages:	2471 - 2474
ISBN:	3-936338-24-8
Paper DOI:	10.4229/23rdEUPVSEC2008-3AV.2.42
Price:	0,00 EUR
Document(s):	paper

Abstract/Summary:

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Transparent conducting oxide (TCO) is one of the key components in photovoltaic and display applications. One candidate to replace indium tin oxide as TCO material is tin oxide. It is stable at high temperature, economical to produce and more benign compared to other TCO materials. The bulk resistivity of tin oxide films deposited with conventional methods (PECVD, spray pyrolysis, atmospheric pressure CVD) reaches as low as 5x10-4 Ohm-cm. However, the deposition temperature is typically above 350°C which limits temperature sensitive processes such as quantum dots based solar cells or large area plastic substrates. We developed a novel PECVD system to deposit tin oxide at lower temperature (below 130°C) while achieving good conductivity. Our tin oxide films have bulk resistivity of 2.18x10-3 Ohm-cm at 130°C which is lower than conventionally deposited films at the same process temperature. Furthermore, the linear PECVD source used in this process is scalable to several meter-wide web substrates with film uniformity better than 3%. The deposition rate is typically 200-300 nm-meter/minute. In the present work, we will discuss the PECVD source used in the process, electrical property (carrier concentration and mobility), optical property and microstructure of the deposited tin oxide based TCO.