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DOE OSTI · 2584561

Poly-Si Passivating Contacts Hydrogenation by Microwave Annealing

Truong, Thien [National Renewable Energy Lab., Golden, CO (United States)] (ORCID:0000000240827999)·Liang, Wensheng [Australian National University]·Basnet, Rabin [Australian National University]·Nemeth, William [National Renewable Energy Lab., Golden, CO (United States)]·Stradins, Paul [National Renewable Energy Lab., Golden, CO (United States)]·Young, David [National Renewable Energy Lab., Golden, CO (United States)]·Macdonald, Daniel [Australian National University]·Fong, Kean [Australian National University]
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Abstract

Hydrogenation is a crucial step in the fabrication of high-efficiency silicon solar cells. In this study, we demonstrate the for the first time effectiveness of hydrogen activation via microwave annealing of hydrogen-rich dielectrics coated on poly-Si passivating contacts. This method is compared with conventional hydrogenation techniques, such as annealing in N2 in the presence of a hydrogen-rich source (such as hydrogenated aluminum oxide (AlOx:H), hydrogenated silicon nitride (SiNy:H), or a AlOx:H/SiNy:H stack). Key improvements observed include a reduction in J0 from 30 to <5 fA/cm2, an increase in iVoc from 690 to >730 mV, and an enhancement in effective lifetime (teff) from 0.6 to ~3.5 milliseconds on phosphorus-doped poly-Si/SiO2 passivating contact samples. With a very short annealing time of ~1-2 minutes, the samples passivated by AlOx:H, SiNy:H, or the stack show similar performance to samples subjected to 30 minutes of nitrogen annealing. Photoluminescence (PL) spectra corroborate our findings regarding the hydrogenation of the poly-Si layer and the c-Si substrate, with an increase in PL intensity after microwave annealing. Ultimately, our work suggests that microwave annealing could be a promising addition, offering flexibility to traditional firing hydrogenation processes.

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14 SOLAR ENERGY36 MATERIALS SCIENCEhydrogenationmicrowave annealingpassivating contactspoly-Si

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Truong, Thien [National Renewable Energy Lab., Golden, CO (United States)] (ORCID:0000000240827999), Liang, Wensheng [Australian National University], Basnet, Rabin [Australian National University], Nemeth, William [National Renewable Energy Lab., Golden, CO (United States)], Stradins, Paul [National Renewable Energy Lab., Golden, CO (United States)], Young, David [National Renewable Energy Lab., Golden, CO (United States)], Macdonald, Daniel [Australian National University], Fong, Kean [Australian National University]. 2025-08-18. Poly-Si Passivating Contacts Hydrogenation by Microwave Annealing. https://doi.org/10.2172/2584561

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