Implementation of a Comprehensive On-Line Closed-Loop Diagnostic System for Roll-to-Roll Amorphous Silicon Solar Cell Production: Final Subcontract Report, 23 April 2003 - 30 September 2006

This report summarizes Energy Conversion Devices' diagnostic systems that were developed in this program, as well as ECD's other major accomplishments. This report concentrates on work carried out in the final (third) phase of this program, beginning in the fall of 2004 and ending in the fall of 2006. ECD has developed a comprehensive in-situ diagnostic system that: Reduces the time betweendeposition in the a-Si machine and device characterization from about 200 h to about 1 h; The Photovoltaic Capacitive Diagnostic systems measure the open-circuit voltage and charging rate (a measure of the short-circuit current) and intra-cell series resistance for each cell in the triple-junction device prior to deposition of the top conductive-oxide coating in a subsequent deposition machine.These systems operate with an rms precision of about 0.03% and have operated for almost 4 years with no need for servicing of the electronics or for calibration; Spectrometers are used to measure the ZnO thickness of the backreflector, a Si thickness, and top conductive-oxide, coatings.