태양전지 응용을 위한 PECVD 실리콘 질화막 증착 및 열처리 최적화

PECVD Silicon Nitride Film Deposition and Annealing Optimization for Solar Cell Application


초록

Plasma enhanced chemical vapor deposition(PECVD) is a well established technique for the deposition of hydrogenated film of silicon nitride (SiNx:H), which is commonly used as an antireflection coating as well as passivating layer in crystalline silicon solar cell. PECVD-SiNx:H films were investigated by varying the deposition and annealing conditions to optimize for the application in silicon solar cells. By varying the gas ratio (ammonia to silane), the silicon nitride films of refractive indices 1.85 - 2.45 were obtained. The film deposited at $450^{\circ}C$ showed the best carrier lifetime through the film deposition rate was not encouraging. The film deposited with the gas ratio of 0.57 showed the best carrier lifetime after annealing at a temperature of $800^{\circ}C$. The single crystalline silicon solar cells fabricated in conventional industrial production line applying the optimized film deposition and annealing conditions on large area substrate of size $125mm{\times}125mm$ (pseudo square) was found to have the conversion efficiencies as high as 17.05 %. Low cost and high efficiency silicon solar cells fabrication sequence has also been explained in this paper.

키워드

참고문헌

  1. Lauinger T, Schmidt J, Aberle AG, and Hezel R, 'Record low surface recombination velocities on 1 ${\Omega}$cm p-silicon using remote plasma silicon nitride passivation', Applied Physics Letters. Vol. 68, pp. 1232-1234, 1996 https://doi.org/10.1063/1.115936
  2. Hezel R, and Jaeger K, 'Low temperature surface passivation of silicon for solar cells', J. Electrochem. Soc. Vol. 136, pp. 518 1989 https://doi.org/10.1149/1.2096673
  3. C. Leguijt, P. LoK 1gen, J. A. Eikelboom, A. W. Weeper, F. M. Schuurmans, W. C. Sinke, P. F. A. Alkemade, P. M. Sarro, C. H. M. Maree, L. A. Verhoef, 'Low temperature surface passivation for silicon solar cells', Solar Energy Materials and Solar Cells. Vol. 40, pp. 297, 1996 https://doi.org/10.1016/0927-0248(95)00155-7
  4. A D. S. Ruby, W. L. Wilbanks, and C. B. Fleddermann, Proceedings of the World Conference on Photovoltaic Energy Conversion, Hawaii 1335 (IEEE, New York, 1994)
  5. W. A. P. Claassen, W. G. J. N. Valkenburg, M. F. C. Willemsen, and W. M. V. D. Wijgert, 'Influence of deposition temperature, gas pressure, gas phase composition, and RF frequency on composition and mechanical stress of plasma silicon nitride layers' J. Electrochem. Soc. Vol. 132, pp. 893 1985 https://doi.org/10.1149/1.2113980
  6. J. Kim, J. Hong, and Soo Hong Lee, 'Application of PECVD SiNx films to screen-printed multicrystalline solar cell' J. Korean Phys. Soc. Vol. 44, pp. 479, 2004
  7. Ji Youn Lee, Soo Hong Lee, 'Application of various surface passivation layers in solar cells', J. Korean Phys. Soc. Vol. 45, pp. 558, 2004
  8. C. H. Ling, C. Y. Kwok, and K. Prasad,'Silicon nitride films prepared by plasma enhanced chemical vapour deposition (PECVD) of SiH4/NH3/N2 Mixtures : some physical properties', Jpn. J. Appl, Phys. Lett. Vol. 25, pp. 1490-1494 1986 https://doi.org/10.1143/JJAP.25.1490
  9. Stefaan De Wolf, Guido Agostinelli, and Guy Beaucarne, 'Influence of stoichiometry of direct plasma-enhanced chemical vapor deposited SiNx films and silicon substrate surface roughness on surface passivation', Journal of Applied Physics. Vol. 97, pp. 063303-4, 2005 https://doi.org/10.1063/1.1861138
  10. W. D. Brown and M. A. Khaliq, 'The effects of rapid thermal annealing on the properties of plasma-enhanced chemically vapor deposited silicon nitride', Thin Solid Films Vol. 186, pp. 73-85, 1990 https://doi.org/10.1016/0040-6090(90)90501-4
  11. J. C. Bruyere, B. Reynes, C. Savall, and C. Roch, 'Annealing of silicon nitride thin films prepared by plasma-enhanced chemical vapor deposition with helium dilution', Thin Solid Films Vol. 221, pp. 65-71, 1992 https://doi.org/10.1016/0040-6090(92)90797-F
  12. Guillermo Santana, and Arturo Morales-Acevedo, 'Optimization of PECVD SiN:H films for silicon solar cells' Solar Energy Materials and Solar Cells. Vol. 60, pp. 137, 2000 https://doi.org/10.1016/S0927-0248(99)00078-1