Title :
Optimized aluminum back surface field techniques for silicon solar cells
Author :
Narasinha, S. ; Rohatgi, A.
Author_Institution :
Dept. of Electr. & Comput. Eng., Georgia Inst. of Technol., Atlanta, GA, USA
fDate :
29 Sep-3 Oct 1997
Abstract :
Screen-printed Al and rapid thermal alloying have been combined in order to achieve an Al back surface field (Al-BSF) which lowers the effective back surface recombination velocity to 200 cm/s on 2.3 Ωcm Si. This Al-BSF process has been integrated into a high-efficiency, laboratory fabrication sequence as well as a high-throughput, industrial-type process in order to achieve solar cell efficiencies in excess of 19.0% and 17.0%, respectively, on 2.3 Ωcm FZ Si. For both process sequences, the efficiency values are 1-2 absolute percentage points higher than cells made with unoptimized Al-BSFs. The critical process requirements for optimal Al-BSF formation are: (1) the use of a fast ramp rate to reach the alloying temperature; and (2) thick film Al deposition prior to alloying
Keywords :
aluminium; elemental semiconductors; semiconductor device manufacture; semiconductor device testing; silicon; solar cells; surface recombination; thick films; 2.3 ohmcm; 200 cm/s; Al; Si; alloying temperature; aluminum back surface field techniques; back surface recombination velocity; critical process requirements; float zone silicon; laboratory fabrication; production process; ramp rate; rapid thermal alloying; screen printing; silicon solar cells; thick film deposition; Alloying; Aluminum; Fabrication; Laboratories; Photovoltaic cells; Rapid thermal processing; Silicon; Temperature; Textile industry; Thick films;
Conference_Titel :
Photovoltaic Specialists Conference, 1997., Conference Record of the Twenty-Sixth IEEE
Conference_Location :
Anaheim, CA
Print_ISBN :
0-7803-3767-0
DOI :
10.1109/PVSC.1997.653925
