Passivation effect of tunnel oxide grown by N2O plasma for c-Si solar cell applications

Jeon, Minhan; Kang, Jungwon; Shim, Gyeongbae; Ahn, Shihyun; Balaji, Nagarajan; Park, Cheolmin; Lee, Youn-Jung; Yi, Junsin

doi:10.1016/j.vacuum.2017.03.035

Cited by 19 publications

(18 citation statements)

References 15 publications

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“…The acronym polysilicon on oxide (POLO) stands for “poly-Si on oxide,” whereas TOPCon denotes “tunneling oxide passivating contact” . In terms of process technology, intrinsic or doped amorphous silicon (a-Si) layers are deposited by low-pressure chemical vapor deposition (LPCVD) , or plasma-enhanced chemical vapor deposition (PECVD) , on top of thermally, , wet-chemically, ,, or PECVD − grown SiO x . The conversion from amorphous to polycrystalline silicon (poly-Si) is done during a high-temperature annealing process .…”

Section: Introductionmentioning

confidence: 99%

Firing-Stable PECVD SiO_xN_y/n-Poly-Si Surface Passivation for Silicon Solar Cells

Stöhr

Aprojanz

Brendel

et al. 2021

ACS Appl. Energy Mater.

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Passivating contacts based on SiO x /poly-Si exhibit excellent contact and surface passivation properties enabling very high solar cell conversion efficiencies. In this paper, we investigate and optimize the plasmaenhanced chemical vapor deposition (PECVD) of SiO x N y /n-a-Si stacks, their subsequent annealing to SiO x N y /n-poly-Si stacks followed by PECVD SiN x deposition and firing. We eliminate blistering of the poly-Si layer by enabling a controlled hydrogen out-diffusion during the annealing step. Whereas the J 0 of thermal SiO x /n-poly-Si stacks degrade after firing, PECVD SiO x N y /n-poly-Si stacks exhibit excellent firing stability enabling J 0 values down to 1.3 fA/cm 2 after firing which corresponds to an outstanding implied V OC of 744 mV. The application of different hydrogenation processes to the thermal SiO x /n-poly-Si and PECVD SiO x N y /n-poly-Si stacks reveals that both stacks achieve excellent passivation properties with J 0 = 1.5 fA/cm 2 after maximum hydrogenation. However, only the PECVD SiO x N y /n-poly-Si stack maintains this excellent surface passivation after firing possibly due to a superior capability to retain the hydrogen at the c-Si/SiO x N y interface during firing and thus demonstrates the potential as a future manufacturing process sequence.

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Section: Introductionmentioning

confidence: 99%

Firing-Stable PECVD SiO_xN_y/n-Poly-Si Surface Passivation for Silicon Solar Cells

Stöhr

Aprojanz

Brendel

et al. 2021

ACS Appl. Energy Mater.

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“…In this work, we developed a plasma‐based method to realize nanometer‐scale SiO x layers, compatible with high‐throughput solar cell processing. [ 15 ] We grow in situ SiO x by exposing c‐Si wafers to a CO 2 plasma prior to plasma‐enhanced CVD (PECVD) of the doped Si layer, using the same reactor for both processes. CO 2 is a commonly available precursor gas in PECVD reactors; recent work discussed plasma‐assisted oxidation using N 2 O.…”

Section: Figurementioning

confidence: 99%

“…In this respect, in situ oxide growth, combined with low pressure chemical vapor deposited (LPCVD) poly-Si may be appealing, but is inherently nonselective, coating both wafer sides, again increasing device fabrication complexity.In this work, we developed a plasma-based method to realize nanometer-scale SiO x layers, compatible with high-throughput solar cell processing. [15] We grow in situ SiO x by exposing c-Si wafers to a CO 2 plasma prior to plasma-enhanced CVD (PECVD) of the doped Si layer, using the same reactor for both processes. CO 2 is a commonly available precursor gas in PECVD reactors; recent work discussed plasma-assisted oxidation using N 2 O.…”

mentioning

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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“…In this work, we developed a plasma-based method to realize nanometer-scale SiOx layers, compatible with high-throughput solar cell processing [15] . We grow in-situ SiOx by exposing c-Si wafers to a CO2 plasma prior to plasma-enhanced CVD (PE-CVD) of the doped Si layer, using the same reactor for both processes.…”

Section: Introductionmentioning

confidence: 99%

“…We grow in-situ SiOx by exposing c-Si wafers to a CO2 plasma prior to plasma-enhanced CVD (PE-CVD) of the doped Si layer, using the same reactor for both processes. CO2 is a commonly available precursor gas in PE-CVD reactors; recent work discussed plasma-assisted oxidation using N2O [15,16] . We remark that achieving excellent surface passivation is known to be more challenging for hole-collecting than for electron-collecting passivating contacts [7,17] , hence our focus on poly-Si(p + )/SiOx/c-Si structures in this work.…”

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

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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, 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 .

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Passivation effect of tunnel oxide grown by N2O plasma for c-Si solar cell applications

Cited by 19 publications

References 15 publications

Firing-Stable PECVD SiO_xN_y/n-Poly-Si Surface Passivation for Silicon Solar Cells

Firing-Stable PECVD SiO_xN_y/n-Poly-Si Surface Passivation for Silicon Solar Cells

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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Passivation effect of tunnel oxide grown by N2O plasma for c-Si solar cell applications

Cited by 19 publications

References 15 publications

Firing-Stable PECVD SiOxNy/n-Poly-Si Surface Passivation for Silicon Solar Cells

Firing-Stable PECVD SiOxNy/n-Poly-Si Surface Passivation for Silicon Solar Cells

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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Firing-Stable PECVD SiO_xN_y/n-Poly-Si Surface Passivation for Silicon Solar Cells

Firing-Stable PECVD SiO_xN_y/n-Poly-Si Surface Passivation for Silicon Solar Cells