Silicon web process development. Annual report

Technical Report · Mon Jun 30 04:00:00 EDT 1980

DOI:https://doi.org/10.2172/5355496· OSTI ID:5355496

Duncan, C S; Seidensticker, R G; McHugh, J P; Hill, F E; Skutch, M E; Driggers, J M; Hopkins, R H

During this reporting period significant milestones have been met. A new barrier crucible design which consistently maintains melt stability over long periods of time has been successfully tested and used in long growth runs. The pellet feeder for melt replenishment was operated continuously for growth runs of up to 17 hours (a one day growth cycle). The liquid level sensor comprising a laser/sensor system was operated, performed well, and meets the requirements for maintaining liquid level height during growth and melt replenishment. An automated feedback loop connecting the feed mechanism and the liquid level sensing system was designed and constructed and, during the preparation of this report, operated successfully for 3 1/2 hours demonstrating the feasibility of semi-automated dendritic web growth. The web throughput task has resulted in a demonstration of wider good quality web as well as a demonstration of higher throughput rates. The accomplishments during the report period are described in detail. The economic analysis of the dendritic web process was updated. The sensitivity of the cost of sheet to variations in capital equipment cost and recycling dendrites was calculated; and it was shown that these factors have relatively little impact on sheet cost. An important finding was that dendrites from web which had gone all the way through the solar cell fabrication process, when melted and grown into web, produce crystals which show no degradation in cell efficiency. Material quality remains high and cells made from web grown at the start, during, and the end of a run from a replenished melt show comparable efficiencies.

• Research Organization: Westinghouse Research and Development Center, Pittsburgh, PA (USA)
• DOE Contract Number: NAS-7-100-954654
• OSTI ID: 5355496
• Report Number(s): DOE/JPL/954654-80/11
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
AUTOMATION
CAPITALIZED COST
CONTROL SYSTEMS
COST
CRYSTAL DEFECTS
CRYSTAL GROWTH
CRYSTAL GROWTH METHODS
CRYSTAL STRUCTURE
CRYSTALS
DENDRITES
DENDRITIC WEB GROWTH METHOD
DIMENSIONS
DIRECT ENERGY CONVERTERS
DISLOCATIONS
ECONOMIC ANALYSIS
ECONOMICS
ELEMENTS
EQUIPMENT
FABRICATION
FEEDBACK
LEVEL INDICATORS
LINE DEFECTS
MEASURING INSTRUMENTS
MELTING
PERFORMANCE
PHASE TRANSFORMATIONS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
RESEARCH PROGRAMS
SEMIMETALS
SHEETS
SILICON
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
VELOCITY
WIDTH