Rapid thermal processing and screen-printing for low cost silicon solar cells
Rapid and potentially low-cost process techniques are analyzed and applied toward the fabrication of high-efficiency Si solar cells. First, a high quality screen-printed (SP) contact methodology is developed that results in fill factors of 0.785-0.790 on monocrystalline Si. Next, aluminum back surface field (Al-BSF) formation is studied in detail to establish the process conditions that result in optimal BSF action. Screen-printing of Al conductor paste and rapid thermal processing (RTP) are integrated into the BSF procedure, and effective recombination velocities (S{sub eff}) as low as 200 cm/s are demonstrated on 2.3 {Omega}-cm Si with this RTP SP Al-BSF process. A novel passivation scheme consisting of a dielectric stack (plasma silicon nitride on top of a rapid thermal oxide) is developed to reduce the surface recombination velocity (S) to {approx}10 cm/s at the 1.3 {Omega}-cm Si surface. The important feature of this stack passivation scheme is its ability to withstand a high-temperature anneal (700{endash}850&hthinsp;{degree}C) without degradation in S. This feature is critical for most current commercial processes that utilize SP contact firing. Finally, the individual processes are integrated to form high-efficiency, manufacturable devices. Solar cell efficiencies of 17{percent} and {gt}19{percent} are achieved on FZ Si with SP and evaporated (photolithography) contacts, respectively. {copyright} {ital 1999 American Institute of Physics.}
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 700940
- Report Number(s):
- CONF-980935-; ISSN 0094-243X; TRN: 9915M0056
- Journal Information:
- AIP Conference Proceedings, Vol. 462, Issue 1; Conference: 15. National Center for Photovoltaics program review conference, Denver, CO (United States), 9-11 Sep 1998; Other Information: PBD: Mar 1999
- Country of Publication:
- United States
- Language:
- English
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