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U.S. Department of Energy
Office of Scientific and Technical Information

Flat-plate solar array project process development area. Process research of non-CZ silicon material. Quarterly report No. 1, November 4, 1983-December 31, 1983

Technical Report ·
DOI:https://doi.org/10.2172/5281929· OSTI ID:5281929

In this program the fabrication of solar cells on N-base silicon using simultaneous diffusion of liquid boron and phosphorus dopants to form the desired P/sup +/NN/sup +/ cell structure will be studied. This simultaneous junction formation method will be compared to the sequential junction formation method where phosphorus will be diffused first to form an N/sup +/N back surface field followed by a boron diffusion for the P/sup +/N front junction. In the standard Westinghouse baseline sequence, P-type dendritic web silicon crystals are grown and processed into solar cells. Simultaneous junction processing dictates the use of N-base crystals in order to reverse the front and rear junction dopants. With this reversal, the faster diffusing (phosphorus) will form the deeper back junction while the slower diffusing source (boron) will form the more shallow front junction. During this period, several lots of N-type crystals were grown on standard Westinghouse pre-pilot line dendritic web growth furnaces. Growth parameters and growth characteristics were not affected by the switch from boron doped to phosphorus doped silicon charges. Several experiments have been carried out to define the gas compositions and flows and the oxide stripping solutions required to produce a stain-free surface on the cell. Any residual staining after diffusion, especially on the P/sup +/ (sun) side of the cell, has been found to degrade cell performance.

Research Organization:
Westinghouse Electric Corp., Pittsburgh, PA (USA). Advanced Energy Systems Div.
DOE Contract Number:
NAS-7-100-956616
OSTI ID:
5281929
Report Number(s):
DOE/JPL/956616-1; WAESD-TR-84-0001; ON: DE84006397
Country of Publication:
United States
Language:
English