Improved beam processing for terrestrial solar cells

Conference · Fri Jan 01 04:00:00 EST 1982

OSTI ID:7065848

Young, R T; Van der Leeden, G A; Westbrook, R D; Sandstrom, R L; Levatter, J I

The major difficulties at present in using laser beam processing for terrestrial solar cells are (1) lack of a suitable laser for large volume cell production; and (2) expense and low throughput of conventional ion implantation, especially for the low energy (5 to 10 keV), high dose (5 x 10/sup 15/cm/sup -2/) implantation needed to obtain shallow p-n junctions. It is shown that these problems may be solved by using simple glow discharge implantation equipment and an XeCl excimer laser for annealing. Preliminary results indicate that with this combination, p/sup +/n Si solar cells with efficiencies of 15% AM1 can be readily obtained without any back surface field. These efficiencies are much better than previously reported values of 11% obtained with glow discharge implantation and ruby laser annealing. Because of the shallow implant (1kV) and high discharge current (a few mA) from the glow discharge implantation and the extremely uniform laser beam from the excimer laser, cells with very shallow junctions (approx. 0.15..mu..m) and low sheet resistivity (approx. 20 ..cap omega../sq. cm) are obtained. As a result, the front surface metal coverage of the cells can be reduced to approx. 5% while retaining very good fill factors (0.77 to 0.80). Furthermore, the blue response of the cells is extremely good.

• Research Organization: Oak Ridge National Lab., TN (USA); Helionetics, Inc., San Diego, CA (USA). Laser Div.
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 7065848
• Report Number(s): CONF-820906-3; ON: DE82022337
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRIC CONDUCTIVITY
ELECTRIC DISCHARGES
ELECTRICAL PROPERTIES
EQUIPMENT
GAS LASERS
GLOW DISCHARGES
ION IMPLANTATION
LASERS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
QUANTUM EFFICIENCY
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SPECTRAL RESPONSE