Rapid thermal processing to enhance PECVD SiN-induced hydrogenation in high-efficiency EFG silicon solar cells

Author

Jeong, J.-W. ; Cho, Y.H. ; Rohatgi, A. ; Rosenblum, M.D. ; Bathey, B.R. ; Kalejs, J.P.

Author_Institution

Sch. of Electr. & Comput. Eng., Georgia Inst. of Technol., Atlanta, GA, USA

fYear

2002

fDate

19-24 May 2002

Firstpage

250

Lastpage

253

Abstract

Rapid thermal processing (RTP) is studied to improve the bulk lifetime and efficiency of EFG Si solar cells. The RTP firing of PECVD SiN on the front and screen-printed Al on the back at 750°C with a fast cooling rate is found to increase the bulk lifetime of EFG Si from 1-3 μs to ∼50 μs due to enhanced SiN-induced hydrogen passivation of defects. This increase is believed to be enhanced due to a synergistic interaction between atomic hydrogen and vacancies. For screen-printed EFG Si solar cells, RTP firing is found to be superior to a conveyor belt furnace firing, resulting in 0.4% higher average absolute cell efficiency. Rapid firing improves back surface field, contacts, and retention of hydrogen at defects. An optimized RTP firing process produces high-efficiency EFG Si solar cells with single layer SiN antireflection coating: 15% efficiency with screen-printed contacts and 15.8% efficiency with photolithography contacts.

Keywords

antireflection coatings; carrier lifetime; cooling; crystal growth from melt; elemental semiconductors; hydrogenation; ohmic contacts; passivation; photolithography; plasma CVD; rapid thermal processing; semiconductor growth; silicon; silicon compounds; solar cells; thick films; vacancies (crystal); 1 to 50 mus; 15 percent; 15.8 percent; 750 degC; EFG Si solar cells; PECVD SiN-induced hydrogenation; RTP firing; SiN-Si:H-Al; absolute cell efficiency; atomic hydrogen; back; back surface field; bulk lifetime; contacts; defects; efficiency; enhanced SiN-induced hydrogen passivation; fast cooling rate; front; high-efficiency EFG silicon solar cells; hydrogen retention; optimized RTP firing process; photolithography contacts; rapid thermal processing; screen-printed Al; screen-printed contacts; simultaneous annealing condition; single layer SiN antireflection coating; synergistic interaction; vacancies; Belts; Coatings; Cooling; Firing; Furnaces; Hydrogen; Passivation; Photovoltaic cells; Rapid thermal processing; Silicon compounds;

fLanguage

English

Publisher

ieee

Conference_Titel

Photovoltaic Specialists Conference, 2002. Conference Record of the Twenty-Ninth IEEE

ISSN

1060-8371

Print_ISBN

0-7803-7471-1

Type

conf

DOI

10.1109/PVSC.2002.1190503

Filename

1190503