Abstract
Emitter surface passivation by low temperature plasma enhanced chemical vapor deposition (PECVD) silicon nitride is investigated and optimized in this paper. We have found that the saturation current density of a 90±10 μ/sq phosphorus diffused emitter with Ns ≈3 x 1019 and Xj ≈0.3 µm can be lowered by a factor of eight by appropriate PECVD silicon nitride deposition and photoassisted anneal. PECVD silicon nitride deposition alone reduces the emitter saturation density (Joe) by about a factor of two to three, and a subsequent photoanneal at temperatures ≥350°C reduces Joe by another factor of three. In spite of the larger flat band shift for direct PECVD silicon nitride coating, the silicon nitride induced surface passivation is found to be about a factor of two inferior to the thermal oxide plus PECVD silicon nitride passivation due to higher interface state density at the SiN/SiO2 interface compared to SiO2/Si interface. A combination of statistical experimental design and neural network modeling is used to show quantitatively that lower radio frequency power, higher substrate temperature, and higher reactor pressure during the PECVD deposition can reduce the Joe of the silicon nitride coated emitter.
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References
A. Wang, J. Zhao, S.R. Wenham and M. A. Green, Appl. Phys. Lett. 64, 199 (1994).
J. Zhao, A. Wang, P. Altermatt and M.A. Green, Appl. Phys. Lett. 66, 3636 (1995).
R.R. King, R.A. Sinton and R.M. Swanson, Appl. Phys. Lett. 54, 15 (1989).
A.W. Blakers and M.A. Green, Appl. Phys. Lett. 47, 818 (1985).
R.A. Sinton, R.R. King and R.M. Swanson, Proc. 4th IEEE Photovolt, sci. Eng. Conf., 638 (1989).
M. Spitzer and C.J. Keavney, Proc. 18th IEEE Photovolt, special. Conf. 43 (1985).
D.E. Kane and R.M. Swanson, Proc. 18th IEEE Photovolt. Special. Conf. 578 (1985).
M.A. Green, A.W. Blakers, Shijiqun, E.M. Keller and S.R. Wenham, Appl. Phys. Lett. 44, 1163 (1984).
R. Hezel and K. Jaeger, J. Electrochem. Soc. 136,518 (1989).
D.S. Ruby and J.D. Levine, Proc. 11th EC Photovoltaic Solar Energy Conf., 385 (1992).
Z. Chen, S.K. Pang, K. Yasutake and A. Rohatgi, J. Appl. Phys. 74, 2856 (1993).
A.A. Bright, J. Bateyand, E. Tierney,App.Phys.Lett. 58,619 (1991).
T. Yasuda, Y. Ma, S. Habermehl and G. Lucovsky,Appl. Phys. Lett. 60, 431(1992).
W.M. Landford and M. J. Rand, J. Appl. Phys. 49,2473 (1978).
A. Rohatgi, Z. Chen, P. Sana, N. Evers,P. Lolgen, R.A. Steeman, Optoelectronics-Devices and Technologies 9, 523 (1994).
To be published, IEEE Trans. Semi. Manufac. May 1996 by S. Han, L. Cai, G. May and A. Rohatgi.
C. Box, W. Hunter and J. Hunter, Statistics for Experimenters, (New York, Wiley, 1978).
G.E.P. Box, W.G. Hunter and J.S. Hunter, Statistics for Experimenters, (New York: John Wiley & Sons, 1978).
D.E. Kane and R.M. Swanson, Proc. 18th IEEE Photovolt. Special. Conf., 578 (1985).
R.R. King, R.A. Sinton and R.M. Swanson, IEEE Trans. Electron Dev. 17, 365 (1990).
D.E. Kane and R.M. Swanson, 18th IEEE PVSC, 578(1985).
G. May, J. Huang and C. Spanos, IEEE Trans. Semi. Manufac., 4, 83 (1991).
C. Himmel and G. May, IEEE Trans. Semi. Manufac. 6,103 (1993).
C. Bose and H. Lord, Applications of Artfiicial Neural Networks, (SPIE, 1993), p. 521.
R. Lippman, IEEE ASSP Mag. Apr. 1987.
D. Rumelhart and J. McClelland, Parallel Distributed Processing, 1. Cambridge: MIT Press, 1986.
F. Nadi, UC-Berkeley ERL Memo. No. UCB/ERL M89/123, Nov. 1986.
K. Yasutake, Z. Chen, S.K. Pang and A. Rohatgi, J. Appl. Phys. 75, 48 (1994).
A.G. Aberle and R. Hezel, to be published in 25th PVSC Proc. 1996. $
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Cai, L., Han, S., May, G. et al. Optimization of saturation current density of PECVD SiN coated phosphorus diffused emitters using neural network modeling. J. Electron. Mater. 25, 1784–1789 (1996). https://doi.org/10.1007/s11664-996-0036-x
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DOI: https://doi.org/10.1007/s11664-996-0036-x