Nitric acid oxidation of Si method for improvement of crystalline Si solar cell characteristics by surface passivation effect

Matsumoto, Tetsuya; Hirose, Ryo; Shibata, Fumiaki; Ishibashi, Daisuke; Ogawara, S.; Kobayashi, Hikaru

doi:10.1016/j.solmat.2014.11.040

Cited by 19 publications

(11 citation statements)

References 40 publications

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“…(a), (b); it is evident that in the case of SiN x , a 1–2 nm SiO x layer is present if the cleans involved an oxide‐last step, whereas no SiO x layer is observed for cleans with an HF‐last step. It has previously been reported that a wet‐chemically grown SiO x interlayer leads to higher effective carrier lifetimes due to a significant reduction in D it,midgap . It has been further reported that D it,midgap of SiN x passivated surfaces for cleans with an oxide‐last step are about 3.6–3.8 · 10 11 eV −1 cm −2 , which is about an order of magnitude lower than D it,midgap values of 1.3–1.4 · 10 12 eV −1 cm −2 reported for cleans with an HF‐last step .…”

Section: Resultsmentioning

confidence: 89%

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Transmission electron microscopy based interface analysis of the origin of the variation in surface recombination of silicon for different surface preparation methods and passivation materials

Ali

Moldovan

Mack

et al. 2017

Physica Status Solidi (a)

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In this work, the root cause of variation in surface recombination for Si wafers after different cleaning processes and for different passivation layers is investigated using a combination of calibrated photoluminescence (PL) imaging and transmission electron microscopy (TEM). The use of a HF-last or oxide-last cleaning and/or conditioning process is shown to have a strong impact on surface recombination for SiNx passivated surfaces, but little impact for Al2O3/SiNx stacks. For a SiNx passivation layer, cross-sectional TEM imaging revealed the formation of a â1-2nm SiOx interlayer resulting from a controlled oxidation during the last cleaning/conditioning step. The presence of the SiOx layer reduces the interface defect density (Dit,midgap) by an order of magnitude and dramatically increases the effective carrier lifetime. However, for Al2O3/SiNx passivated surfaces, TEM studies revealed that a SiOx layer is formed at the interface between the c-Si and AlOx even for c leaning processes ending with HF-last treatment due to which the cleaning sequence has minimal impact on the effective carrier lifetime

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Section: Resultsmentioning

confidence: 89%

“…Bulk recombination can be greatly reduced by using high quality Si wafers free of defects and having high bulk carrier lifetimes (>1 ms). On the other hand, surface recombination is due to the presence of unsatisfied or dangling bonds at the Si surface .…”

Section: Introductionmentioning

confidence: 99%

Transmission electron microscopy based interface analysis of the origin of the variation in surface recombination of silicon for different surface preparation methods and passivation materials

Ali

Moldovan

Mack

et al. 2017

Physica Status Solidi (a)

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“…Silicon oxide (SiO x ) has been extensively studied for the electronic passivation of crystalline silicon (c‐Si) surfaces, with applications in a range of electronic devices, including transistors and solar cells. [ 1,2 ] Increasingly, SiO x is also used in the fabrication of high‐quality carrier‐selective, passivating contacts for c‐Si solar cells, aimed at effectively collecting one carrier type (e.g., holes), while avoiding recombination of the opposite carrier type (e.g., electrons). [ 3 ] In such contacts, the SiO x layer is inserted between the c‐Si surface and a doped polysilicon (poly‐Si) layer; these contacts are therefore sometimes referred to as tunnel‐oxide passivating contacts (TOPCon) [ 4 ] or polysilicon on oxide (POLO) contacts.…”

Section: Figurementioning

confidence: 99%

In Situ Plasma‐Grown Silicon‐Oxide for Polysilicon Passivating Contacts

Alzahrani

Allen

Bastiani

et al. 2020

Adv Materials Inter

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Large‐scale manufacturing of polysilicon‐based passivating contacts for high‐efficiency crystalline silicon (c‐Si) solar cells demands simple fabrication of thermally stable SiOx films with well controlled microstructure and nanoscale thickness to enable quantum‐mechanical tunneling. Here, plasma‐dissociated CO2 is investigated to grow in situ thin (<2 nm) SiOx films on c‐Si wafers as tunnel‐oxides for plasma‐deposited, hole‐collecting (i.e., p‐type) polysilicon contacts. It is found that such plasma processing offers excellent thickness control and superior structural integrity upon thermal annealing at 1000 °C, compared to state‐of‐the‐art wet‐chemical oxides. As a result, p‐type polysilicon contacts are achieved on n‐type c‐Si wafers that combine excellent surface passivation, resulting in an implied open‐circuit voltage exceeding 700 mV, with a contact resistance as low as 0.02 Ω cm2.

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“…Silicon oxide (SiOx) has been extensively studied for the electronic passivation of crystalline silicon (c-Si) surfaces, with applications in a range of electronic devices, including transistors and solar cells [1,2] . Increasingly, SiOx is also used in the fabrication of high-quality carrierselective, passivating contacts for c-Si solar cells, aimed at effectively collecting one carrier type (e.g.…”

Section: Introductionmentioning

confidence: 99%

Passivating Contacts: In Situ Plasma‐Grown Silicon‐Oxide for Polysilicon Passivating Contacts (Adv. Mater. Interfaces 21/2020)

Alzahrani

Allen

Bastiani

et al. 2020

Adv Materials Inter

View full text Add to dashboard Cite

Large-scale manufacturing of polysilicon-based passivating contacts for high-efficiency crystalline silicon (c-Si) solar cells demands simple fabrication of thermally-stable SiOx films with well controlled microstructure and nanoscale thickness to enable quantum-mechanical tunneling. Here, we investigate plasma-dissociated CO2 to grow in-situ thin (< 2nm) SiOx films on c-Si wafers as tunnel-oxides for plasma-deposited, hole-collecting (i.e. p-type) polysilicon contacts. We find that such plasma processing offers excellent thickness control and superior structural integrity upon thermal annealing at 1000 °C, compared to state-of-the-art wetchemical oxides. As a result, we achieved p-type polysilicon contacts on n-type c-Si wafers that combine excellent surface passivation, resulting in an implied open-circuit voltage exceeding 700 mV, with a contact resistance as low as 0.02 Ω•cm 2 .

show abstract

Nitric acid oxidation of Si method for improvement of crystalline Si solar cell characteristics by surface passivation effect

Cited by 19 publications

References 40 publications

Transmission electron microscopy based interface analysis of the origin of the variation in surface recombination of silicon for different surface preparation methods and passivation materials

Transmission electron microscopy based interface analysis of the origin of the variation in surface recombination of silicon for different surface preparation methods and passivation materials

In Situ Plasma‐Grown Silicon‐Oxide for Polysilicon Passivating Contacts

Passivating Contacts: In Situ Plasma‐Grown Silicon‐Oxide for Polysilicon Passivating Contacts (Adv. Mater. Interfaces 21/2020)

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