Restored Passivation after Complete Removal of Front Poly-Si Between the Grid in Poly-Si/SiO2 Front/Back Cells

David Young; Kejun Chen; William Nemeth; Vincenzo La Salvia; San Theingi; Matthew Page; Pauls Stradins

doi:10.1063/5.0089756

Restored Passivation after Complete Removal of Front Poly-Si Between the Grid in Poly-Si/SiO2 Front/Back Cells

David Young, Kejun Chen, William Nemeth, Vincenzo La Salvia, San Theingi, Matthew Page, Pauls Stradins

Chemistry and Nanoscience

Colorado School of Mines

Research output: Contribution to conference › Paper › peer-review

Abstract

This work explores the use of wet chemical etching to completely remove the front poly-Si layer between grid lines of a front/back poly-Si/SiO2 passivated contact device. The purpose of the work is to provide excellent passivation under the metal grid, but to also maximize Jsc by eliminating optical absorption in the front poly-Si. We show that after a high temperature anneal to distribute carriers in the poly-Si/SiO2/c-Si interface all of the poly-Si can be removed selectively with TMAH, using the SiO2 as an etch-stop layer. The etched surface can be repassivated back to its original level with the addition of a SiNx/Al2O3 stack grown on the preserved tunnelling oxide layer followed by a short forming gas anneal. Using symmetric 100 - 200 nm intrinsically doped poly-Si/SiO2 on textured n-type wafer templates we show absolute device efficiency enhancement from 15% to 21% by increasing the Jsc by 12 mA/cm² after removing the front poly-Si and repassivating while effectively preserving the Voc, and FF of the device. IQE values are similar to PERC devices in the short wavelength range.

Original language	American English
Number of pages	5
DOIs	https://doi.org/10.1063/5.0089756 https://doi.org/10.1063/5.0089756
State	Published - 24 Aug 2022
Event	11th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2021 - Hamelin, Virtual, Germany Duration: 19 Apr 2021 → 23 Apr 2021

Conference

Conference	11th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2021
Country/Territory	Germany
City	Hamelin, Virtual
Period	19/04/21 → 23/04/21

Bibliographical note

Publisher Copyright:
© 2022 American Institute of Physics Inc.. All rights reserved.

NREL Publication Number

NREL/CP-5900-84146

Keywords

etching
optical absorption
semiconductor materials

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Cite this

Young, D., Chen, K., Nemeth, W., La Salvia, V., Theingi, S., Page, M., & Stradins, P. (2022). Restored Passivation after Complete Removal of Front Poly-Si Between the Grid in Poly-Si/SiO2 Front/Back Cells. Paper presented at 11th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2021, Hamelin, Virtual, Germany. https://doi.org/10.1063/5.0089756, https://doi.org/10.1063/5.0089756

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abstract = "This work explores the use of wet chemical etching to completely remove the front poly-Si layer between grid lines of a front/back poly-Si/SiO2 passivated contact device. The purpose of the work is to provide excellent passivation under the metal grid, but to also maximize Jsc by eliminating optical absorption in the front poly-Si. We show that after a high temperature anneal to distribute carriers in the poly-Si/SiO2/c-Si interface all of the poly-Si can be removed selectively with TMAH, using the SiO2 as an etch-stop layer. The etched surface can be repassivated back to its original level with the addition of a SiNx/Al2O3 stack grown on the preserved tunnelling oxide layer followed by a short forming gas anneal. Using symmetric 100 - 200 nm intrinsically doped poly-Si/SiO2 on textured n-type wafer templates we show absolute device efficiency enhancement from 15% to 21% by increasing the Jsc by 12 mA/cm2 after removing the front poly-Si and repassivating while effectively preserving the Voc, and FF of the device. IQE values are similar to PERC devices in the short wavelength range.",

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Young, D, Chen, K, Nemeth, W, La Salvia, V, Theingi, S , Page, M & Stradins, P 2022, 'Restored Passivation after Complete Removal of Front Poly-Si Between the Grid in Poly-Si/SiO2 Front/Back Cells', Paper presented at 11th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2021, Hamelin, Virtual, Germany, 19/04/21 - 23/04/21. https://doi.org/10.1063/5.0089756, https://doi.org/10.1063/5.0089756

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AU - Young, David

AU - Chen, Kejun

AU - Nemeth, William

AU - La Salvia, Vincenzo

AU - Theingi, San

AU - Page, Matthew

AU - Stradins, Pauls

PY - 2022/8/24

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N2 - This work explores the use of wet chemical etching to completely remove the front poly-Si layer between grid lines of a front/back poly-Si/SiO2 passivated contact device. The purpose of the work is to provide excellent passivation under the metal grid, but to also maximize Jsc by eliminating optical absorption in the front poly-Si. We show that after a high temperature anneal to distribute carriers in the poly-Si/SiO2/c-Si interface all of the poly-Si can be removed selectively with TMAH, using the SiO2 as an etch-stop layer. The etched surface can be repassivated back to its original level with the addition of a SiNx/Al2O3 stack grown on the preserved tunnelling oxide layer followed by a short forming gas anneal. Using symmetric 100 - 200 nm intrinsically doped poly-Si/SiO2 on textured n-type wafer templates we show absolute device efficiency enhancement from 15% to 21% by increasing the Jsc by 12 mA/cm2 after removing the front poly-Si and repassivating while effectively preserving the Voc, and FF of the device. IQE values are similar to PERC devices in the short wavelength range.

AB - This work explores the use of wet chemical etching to completely remove the front poly-Si layer between grid lines of a front/back poly-Si/SiO2 passivated contact device. The purpose of the work is to provide excellent passivation under the metal grid, but to also maximize Jsc by eliminating optical absorption in the front poly-Si. We show that after a high temperature anneal to distribute carriers in the poly-Si/SiO2/c-Si interface all of the poly-Si can be removed selectively with TMAH, using the SiO2 as an etch-stop layer. The etched surface can be repassivated back to its original level with the addition of a SiNx/Al2O3 stack grown on the preserved tunnelling oxide layer followed by a short forming gas anneal. Using symmetric 100 - 200 nm intrinsically doped poly-Si/SiO2 on textured n-type wafer templates we show absolute device efficiency enhancement from 15% to 21% by increasing the Jsc by 12 mA/cm2 after removing the front poly-Si and repassivating while effectively preserving the Voc, and FF of the device. IQE values are similar to PERC devices in the short wavelength range.

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KW - semiconductor materials

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M3 - Paper

AN - SCOPUS:85137475666

T2 - 11th International Conference on Crystalline Silicon Photovoltaics, SiliconPV 2021

Y2 - 19 April 2021 through 23 April 2021

ER -

Restored Passivation after Complete Removal of Front Poly-Si Between the Grid in Poly-Si/SiO2 Front/Back Cells

Abstract

Conference

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NREL Publication Number

Keywords

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