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Title: Automated array Assembly, Phase II. Quarterly report No. 3, April 1--June 30, 1978

Abstract

The purpose of the overall program is to establish technological readiness and provide verification for the elements of a manufacturing sequence which would ultimately be suitable for the large-scale production of silicon solar-array modules at a selling price of less than $500/kW. A program and process plan for accomplishing this objective was developed and put into operation. This plan is centered around a processing sequence using Czochralski, silicon wafers. Three junction-formation processes are considered since cost analyses show that they do not differ greatly in cost. The progress made in the various process steps of the plan is described, and plans for the next quarter are summarized.

Authors:
Publication Date:
Research Org.:
Alabama A and M Univ., Normal (USA)
OSTI Identifier:
5953511
Report Number(s):
DOE/JPL/954868-3
DOE Contract Number:
NAS-7-100-954868
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; SILICON SOLAR CELLS; PRODUCTION; ANTIREFLECTION COATINGS; AUTOMATION; CONNECTORS; COST; CZOCHRALSKI METHOD; ELECTRIC CONTACTS; ETCHING; INSPECTION; MANUFACTURING; SCREEN PRINTING; SOLAR CELL ARRAYS; SOLDERING; TESTING; COATINGS; CONDUCTOR DEVICES; DEPOSITION; DIRECT ENERGY CONVERTERS; ELECTRICAL EQUIPMENT; EQUIPMENT; FABRICATION; JOINING; PHOTOELECTRIC CELLS; PHOTOVOLTAIC CELLS; SOLAR CELLS; SURFACE COATING; SURFACE FINISHING; WELDING; 140501* - Solar Energy Conversion- Photovoltaic Conversion

Citation Formats

D'Aiello, R. V.. Automated array Assembly, Phase II. Quarterly report No. 3, April 1--June 30, 1978. United States: N. p., 1978. Web. doi:10.2172/5953511.
D'Aiello, R. V.. Automated array Assembly, Phase II. Quarterly report No. 3, April 1--June 30, 1978. United States. doi:10.2172/5953511.
D'Aiello, R. V.. Thu . "Automated array Assembly, Phase II. Quarterly report No. 3, April 1--June 30, 1978". United States. doi:10.2172/5953511. https://www.osti.gov/servlets/purl/5953511.
@article{osti_5953511,
title = {Automated array Assembly, Phase II. Quarterly report No. 3, April 1--June 30, 1978},
author = {D'Aiello, R. V.},
abstractNote = {The purpose of the overall program is to establish technological readiness and provide verification for the elements of a manufacturing sequence which would ultimately be suitable for the large-scale production of silicon solar-array modules at a selling price of less than $500/kW. A program and process plan for accomplishing this objective was developed and put into operation. This plan is centered around a processing sequence using Czochralski, silicon wafers. Three junction-formation processes are considered since cost analyses show that they do not differ greatly in cost. The progress made in the various process steps of the plan is described, and plans for the next quarter are summarized.},
doi = {10.2172/5953511},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jun 01 00:00:00 EDT 1978},
month = {Thu Jun 01 00:00:00 EDT 1978}
}

Technical Report:

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  • Development effort has been applied to front junction and back surface field region formation and to high speed application of AR coatings to ribbon material. Effects on cell performance of various surface preparation procedures for web silicon material have also been studied. Ultrasonic seam bonding of foil interconnects to cell metallization has been identified as a potentially higher throughput, lower cost method of interconnection than producing discrete bonds. Collecting junctions have been made in wafer cells using reagent grade POCl/sub 3/, containing titanium at the 20 ppMa level, and in such material doped with Ti to the 100 and 500more » ppMa levels using TiCl/sub 4/. No electrical effect of Ti doping was detected. Cells with boron diffusions made from boron-doped glasses deposited in a Silox reactor have shown back surface field action to that in cells using glasses formed in a cold wall horizontal reactor. Antireflection coatings of TiO/sub 2/ in the 600 A range of thickness have been prepared by pulling from liquid precursor solutions at speeds ranging to 40 ft/min. Speeds above 10 ft/min are considered necessary for high throughput processing of continuous ribbon silicon. At 25 ft/min, the contribution to selling price of this process is estimated to be about $0.009/peak watt, with the cost of unrecovered alcohol being the major price component. Several methods of preparation of the web silicon surface have been considered with regard to ultimate cell performance.« less
  • Data was gathered and analysis continued on seventeen process groups. Five process groups were completed. They include: solar cell test data acquisition, plasma etching of resist, laser trimming and holing operation, wafer surface preparation and wafer printing. Preliminary results to date show very promising results for other task groups. Silicon nitride antireflective coating equipment with modifications has high potential for low-cost automation. An electroless nickel plating system has been designed and is under construction to demonstrate the processing of 1500 wafers per hour. The conceptual design of two fully automated laser trimming and holing lines has been completed and hasmore » very promising low-cost, high volume potential. The spray-on dopant model equipment construction is nearly completed. Preliminary spray-on tests have shown very good results. Dopants can be sprayed on without wafer edge overlap and good dopant uniformity can be achieved. SAMICS has been applied to most process groups. It has been very effective in analyzing process steps for low-cost potential for meeting the LSA 1986 goals.« less
  • During this period, all tasks progressed according to scheduled plans. This report highlights the process verification efforts, ion implantation investigations, plasma etching, and cost factors in the metallization processes. Completed modules were delivered to JPL to demonstrate the process sequence. A surface film has been observed on ion implanted wafers which was tentatively been associated with break-down of the vacuum pump oil during implantation. A baseline process for plasma patterning of silicon nitride on a silicon substrate has been specified. In addition, copper has been shown to have strong cost advantages over other metals for a conductor layer; and nickelmore » has been identified as a desirable barrier between copper and silicon.« less