DocumentCode :
1557578
Title :
Enhanced silicon solar cell performance by rapid thermal firing of screen-printed metals
Author :
Jeong, Ji-Weon ; Rohatgi, Ajeet ; Yelundur, Vijay ; Ebong, Abasifreke ; Rosenblum, Mark D. ; Kalejs, Juris P.
Author_Institution :
Sch. of Electr. & Comput. Eng., Georgia Inst. of Technol., Atlanta, GA, USA
Volume :
48
Issue :
12
fYear :
2001
fDate :
12/1/2001 12:00:00 AM
Firstpage :
2836
Lastpage :
2841
Abstract :
Rapid thermal processing (RTP) of screen-printed (SP) Al on the back and silver (Ag) grid on the front produced significant improvement in back surface field (BSF) of n+-p-p+ float-zone (FZ) Si solar cells. Two-step firing was found to form more effective BSF than co-firing, resulting in 0.6-1.0% increase in absolute cell efficiency. In addition, RTP was found to be more effective than the beltline processing (BLP), resulting in 0.5-1.0% increase in absolute cell efficiency. Although the Al-BSF formed by the BLP was inferior to the RTP, the difference between the two is virtually eliminated during the subsequent RTP contact firing. Internal quantum efficiency (IQE) analysis of the solar cells gave effective back surface recombination velocities (Seff) of >5000 cm/s and ~1500 cm/s for co-firing in the BLP and the RTP, respectively. Two-step firing produced Seff of ~1500 cm/s and ~700 cm/s in the BLP and the RTP, respectively. However, Seff for the two-step firing, involving BLP BSF formation followed by RTP contact firing, was found to be ~700 cm/s, which indicates that RTP contact firing with a faster ramp-up (100°C/s) restores the poor-quality BLP BSF. On the other hand, BLP contact firing with a slow ramp-up (<10°C/s) degrades the high-quality RTP BSF, increasing Seff from ~700 cm/s to ~1500 cm/s
Keywords :
elemental semiconductors; rapid thermal processing; semiconductor device manufacture; silicon; solar cells; surface recombination; 400 to 850 C; IQE analysis; RTP contact firing; Si solar cell performance enhancement; Si-Ag; Si-Al; absolute cell efficiency; back surface field; back surface recombination velocities; beltline processing; internal quantum efficiency; n+-p-p+ float-zone Si solar cells; open circuit voltage; rapid thermal firing; rapid thermal processing; screen-printed metals; temperature ramp-up; two-step firing; Costs; Fabrication; Firing; Photovoltaic cells; Photovoltaic systems; Radiative recombination; Rapid thermal processing; Silicon; Silver; Solar power generation;
fLanguage :
English
Journal_Title :
Electron Devices, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9383
Type :
jour
DOI :
10.1109/16.974713
Filename :
974713
Link To Document :
بازگشت