Heteroepitaxial Growth of Ge-Rich SiGe Films on Si for Solar Cells

Abstract:

Germanium-rich silicon-germanium (Si_1-xGe_x: 0.98≤x≤1) films were epitaxially grown on Si (001) substrate by reactive thermal chemical vapor deposition at low temperature. Si₂H₆ and GeF₄ were used as source gases. The effect of gas flow ratio between Si₂H₆ and GeF₄ was studied to optimize the film quality. The results indicated that Si_1-xGe_x (x≥0.99) epilayer can be prepared directly on Si wafer at 350°C with a threading dislocation density of ~7×10⁵/cm² and surface RMS roughness of 1.0 nm. Hall-effect and conductivity measurements revealed that the epilayer was p-type conduction with the hall mobility of 767 cm²/Vs and the hole concentration of 6.08×10¹⁶/cm³. Those results indicated the Ge-rich Si_1-xGe_x was an excellent candidate for bottom cells of multijunction solar cells.

• Periodical: Advanced Materials Research (Volume 1014)
• Pages: 216-219
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.1014.216
• Online since: July 2014
• Authors: Jin Wang*, Ke Tao, Guo Feng Li
• Keywords: Bottom Solar Cells, Epitaxial Growth, Silicon-Germanium, Threading Dislocation Density

References

[1] S. A. Healy, M. A. Green, Sol. Energy Mater. Sol. Cells 28 (1992) 273.

[2] E. Borne, J. P. Boyeaux, A. Laugier, First WCPEC, 1994, p.1637.

[3] A. Gutjahr, I. Silier, N. Rollbuhler, M. Konuma, F. Banhart, K. Said, J. Poortmans, Twenty-Sixth PVSC, 1997, p.759.

DOI: 10.1109/pvsc.1997.654200

[4] J. X. Chen, F. Ernst, P. O. Hansson, E. Bauser, J. Cryst. Growth 118 (1992) p.452.

[5] M. T. Currie, S. B. Samavedam, T. A. Langdo, C. W. Leitz, E. A. Fitzgerald, Appl. Phys. Lett. 72 (1998) 1718.

[6] J. M. Hartmann, L. Baud, G. Rolland, J. M. Fabbri, T. Billon, ECS Transactions 3 (2006) 219.

[7] T. H. Loh, H. S. Nguyen, C. H. Tung, A. D. Trigg, G. O. Lo, N. Balasubramanian, D. L. Kwong, S. Tripathy, Appl. Phys. Lett. 90 (2007) 092108.

DOI: 10.1063/1.2709993

[8] D. Choi, Y. Ge, J. S. Harris, J. Cagnon, S. Stemmer, J. Cryst. Growth 310 (2008) 4273.

[9] H. -W. Kim, K. W. Shin, G. -D. Lee, E. Yoon, Thin Solid Films 517 (2009) 3990.

[10] Y. H. Tan, C. S. Tan, Thin Solid Films, 520 (2012) 2711.

[11] Masaji Yamamoto, Jun-ichi Hanna, Masato Miyauchi, Appl. Phys. Lett. 63 (1993) 2508.

[12] Masaji Yamamoto, Yoshiharu Takada, Junichi Hanna, Appl. Phys. Lett. 64 (1994) 3467.

[13] Jun-ichi Hanna, Kousaku Shimizu, J. Organomet. Chem. 611 (2000) 531.

[14] B. O. Kolbesen, J. Mahlib and D. Possner, ECS Transactions 11 (2007) 195.

[15] A. Abbadie, F. Allibert, F. Brunier, Solid-State Electron. 53 (2009) 850.

[16] H. K. Shin, D. J. Lockwood, J. –M. Baribeau, Solid State Commun. 114 (2000) 505.

[17] J. M. Hartmann, B. Gallas, J. Zhang, J. J. Harris, Semicond. Sci. Technol. 15 (2000) 370.

[18] K. Tao, Y. Kurosawa, J. Hanna, Appl. Phys. Lett. 102 (2013) 182109.