Excimer laser annealing to fabricate low cost solar cells. Quarterly technical report No. 2, 1 July-30 September 1984

Technical Report · Mon Oct 01 00:00:00 EDT 1984

DOI:https://doi.org/10.2172/6151766· OSTI ID:6151766

The objective of this research is to determine whether or not pulsed excimer laser annealing (PELA) of ion-implanted junctions is a cost effective replacement for diffused junctions of crystalline silicon solar cells. The preliminary economic analysis completed during the first quarter of this program showed that the use of ion implantation and PELA to fabricate both the front junction and back surface field (BSF) would cost approximately 35 cents per peak watt (Wp), compared to a cost of 15 cents/Wp for a hypothetical baseline diffusion process that it is assumed to yield cells with an average efficiency of 14%. A cost advantage may be attained, however, if the implant-PELA process yields an improvement in the average cell efficiency from 14 to 16%; this improvement would lower the overall cost of the module by about 15 cents/Wp. The technical goal of this research is to develop an optimized PELA process compatible with commercial production, and to demonstrate increased cell efficiency with sufficient product for adequate statistical analysis. During the second quarter of this program, it was shown that the laser chosen for this work, operating with an output power of 50 watts, demonstrated sufficient processing speed for commercial production. Also during this time period, the PELA process was optimized for annealing phosphorus implants in polished p-type silicon wafers. The best solar cell obtained in this way had an efficiency of 10.5% at AM1 illumination withour AR coating. This efficiency is equal to that of co-processed furnace annealed ion-implanted controls. Work planned during the next quarter includes optimization of the PELA process parameters for use with screen printed contacts, optimization of the PELA process for use with texture-etched material, and development of a set of parameters to anneal boron or boron-trifluoride implants.

• Research Organization: Spire Corp., Bedford, MA (USA)
• DOE Contract Number: NAS-7-100-956797
• OSTI ID: 6151766
• Report Number(s): DOE/JPL/956797-02; ON: DE85002508
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
SILICON SOLAR CELLS
ANNEALING
EXCIMER LASERS
FABRICATION
ION IMPLANTATION
LASER-RADIATION HEATING
OPTIMIZATION
DIRECT ENERGY CONVERTERS
EQUIPMENT
GAS LASERS
HEAT TREATMENTS
HEATING
LASERS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PLASMA HEATING
SOLAR CELLS
SOLAR EQUIPMENT
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture