Investigation of Contact Resistivities on APCVD (p) Poly-Si for Fired Passivating Contacts




(p) Poly-Si, FPC, APCVD, Metallization


We investigate the properties of boron doped polycrystalline Si (poly-Si) deposited by atmospheric pressure chemical vapor deposition (APCVD) applied to fired passivating contacts (FPC), where no high temperature annealing takes place apart from the contact firing step. X-ray diffraction measurements show that the APCVD poly-Si is already partially crystallized directly after deposition and the crystallite size further increases during firing. Without metallization an implied open circuit voltage of up to 719 mV is achieved. Screen-printing with an Ag paste yields minimal contact resistivities of down to 1 mΩcm² at high firing temperatures. Furthermore, thicker poly-Si layers, accomplished by driving the same wafer multiple times through the APCVD system, generally correspond to lower contact resistivities for the FPC. This can partly be explained by an increasing crystallinity and conductivity during deposition due to the higher thermal budget during deposition for thicker layers as well as by a larger contact area for thicker poly-Si layers. Scanning electron microscopy on sample cross-sections show that almost the entire poly-Si layer is covered with Ag crystallites at high firing temperatures. For lower temperatures a lower density of Ag crystallites in the poly-Si is visible. Both findings hold for planar and textured surfaces.


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F. Haase, C. Hollemann, S. Schäfer, A. Merkle, M. Rienäcker, J. Krügener, R. Brendel, R. Peibst, “Laser contact openings for local poly-Si-metal contacts enabling 26.1%-efficient POLO-IBC solar cells,” Solar Energy Materials and Solar Cells, vol.186, pp. 184–193, 2018, doi:

T. G. Allen, J. Bullock, X. Yang, A. Javey, S. D. Wolf, “Passivating contacts for crystalline silicon solar cells,” Nature Energy, vol.4, pp. 914–928, Sep., 2019, doi:

A. Ingenito, S. Libraro, P. Wyss, C. Allebé, M. Despeisse, S. Nicolay, F.-J. Haug, C. Ballif, “Implementation and understanding of p⁺ fired rear hole selective tunnel oxide passivating contacts enabling greater conversion efficiency in p-type c-Si solar cells,” Solar Energy Materials and Solar Cells, vol.219, p. 110809, Jan., 2021, doi:

M. Lehmann, N. Valle, J. Horzel, A. Pshenova, P. Wyss, M. Döbeli, M. Despeisse, S. Eswara, T. Wirtz, Q. Jeangros, A. Hessler-Wyser, F.-J. Haug, A. Ingenito, C. Ballif, “Analysis of hydrogen distribution and migration in fired passivating contacts (FPC),” Solar Energy Materials and Solar Cells, vol.200, p. 110018, Sep., 2019, doi:

A. Merkle, S. Seren, H. Knauss, B. Min, J. Steffens, B. Terheiden, R. Brendel, R. Peibst, “Atmospheric pressure chemical vapor deposition of in-situ doped amorphous silicon layers for passivating contacts,” in Proc. 35th EUPVSEC, 2018, pp. 785-791.

M. Fırat, H. S. Radhakrishnan, S. Singh, F. Duerinckx, M. R. Payo, L. Tous, J. Poortmans, “Industrial metallization of fired passivating contacts for n-type tunnel oxide passivated contact (n-TOPCon) solar cells,” Solar Energy Materials and Solar Cells, vol.240, p. 111692, Jun., 2022, doi:

S. Mack, D. Herrmann, M. Lenes, M. Renes, A. Wolf, “Progress in p-type tunnel oxide-passivated contact solar cells with screen-printed contacts,“ Solar RRL, vol.5, no.5, p. 2100152, Mar., 2021, doi:

P. Padhamnath, N. Nampalli, A. Khanna, B. Nagarajan, A. G. Aberle, S. Duttagupta, “Progress with passivation and screen-printed metallization of boron-doped monoPoly™ layers,“ Solar Energy, vol.231, pp. 8–26, Jan., 2022, doi:

J. Wiskel, J. Lu, O. Omotoso, D. Ivey, H. Henein, “Characterization of precipitates in a microalloyed steel using quantitative X-ray diffraction,“ Metals, vol.6, p. 90, Apr., 2016, doi:

A. Chaudhary, J. Hoß, J. Lossen, F. Huster, R. Kopecek, R. van Swaaij, M. Zeman, “Influence of polysilicon thickness on properties of screen-printed silver paste metallized silicon oxide/polysilicon passivated contacts,“ physica status solidi (a), vol.218, p. 2100243, Aug., 2021, doi:

R. Glatthaar, F. Huster, T. Okker, B. C. Greven, S. Seren, G. Hahn, B. Terheiden, “Contact formation of silver paste and atmospheric pressure chemical vapor deposition (n) poly-silicon passivating contacts on planar and textured surfaces,“ physica status solidi (a), vol.219, p. 2200501, Nov., 2022, doi:




How to Cite

Okker, T., Glatthaar, R., Huster, F., Hahn, G., Cela Greven, B., Seren, S., & Terheiden, B. (2024). Investigation of Contact Resistivities on APCVD (p) Poly-Si for Fired Passivating Contacts. SiliconPV Conference Proceedings, 1.

Conference Proceedings Volume


Carrier Selective Contacts, Metallization and Contact Formation

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