Role of silicon surface, polished 〈100〉 and 〈111〉 or textured, on the efficiency of double‐sided TOPCon solar cells

Lozac’h, Mickaël; Nunomura, Shota

doi:10.1002/pip.3304

Cited by 28 publications

(19 citation statements)

References 56 publications

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“…It has been observed that in textured surfaces, the thickness of the oxide and polysilicon can vary, leading to thinner layer stacks at the tips and flanks of the pyramids, as compared with the valleys and flat surfaces. [ 30,31 ] Based on this observation, we suggest that, due to the thinner passivating stack, the tips and flanks of the pyramids are more susceptible to damage caused by the metal paste constituents and hence lead to an overall higher metal polysilicon recombination current density.…”

Section: Resultsmentioning

confidence: 94%

Influence of Silicon Substrate Surface Finish on the Screen‐Printed Silver Metallization of Polysilicon‐Based Passivating Contacts

Chaudhary

Hoß

Lossen

et al. 2022

Physica Status Solidi (a)

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Passivated contact based on a thin interfacial oxide and a highly doped polysilicon layer has emerged as the next evolutionary step to increase the efficiencies of industrial silicon solar cells. To take maximum advantage from this layer stack, it is vital to limit the losses at the metal polysilicon interface, which can be quantified as metal polysilicon recombination current density (J 0met) and contact resistivity. In cell concepts, wherein a large variety of silicon substrate surface finish can be obtained, it is essential to know how the surface finish affects the J 0met and contact resistivity. Herein, commercially available fire through silver paste and the metal‐polysilicon recombination current densities and contact resistivity are used for three different silicon substrate surface finishes, namely: planar or saw damage etched (SDE), chemically polished in acidic solution and alkaline pyramidal textured. Contact resistivity values below 3 mΩ cm2 with J 0met in order of the recombination current density of the doped region (J 0pass) are obtained for samples with planar surface for both 150 and 200 nm n+ polysilicon layer thicknesses. The results presented in this work show that the samples with flat substrate morphology outperform the samples with textured surfaces.

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Section: Resultsmentioning

confidence: 94%

Influence of Silicon Substrate Surface Finish on the Screen‐Printed Silver Metallization of Polysilicon‐Based Passivating Contacts

Chaudhary

Hoß

Lossen

et al. 2022

Physica Status Solidi (a)

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“…This is surprising as usually V oc values beyond 700 mV can be obtained for textured surfaces when using the same oxidation process as for planar surfaces. The difference in passivation on planar and textured surfaces is mainly associated with the varying thickness of the thermally grown SiO x due to the different surface orientations and by the reduced passivation quality of the SiO x interlayer on <111> planes 84–86 . Hence, it could be that during the oxidation process some problems occurred, leading to a thinner SiO x on <111> planes or that other processes like texturing or cleaning were not optimal.…”

Section: Resultsmentioning

confidence: 99%

Polysilicon contact structures for silicon solar cells using atomic layer deposited oxides and nitrides as ultra‐thin dielectric interlayers

Reichel

Feldmann

Richter

et al. 2021

Progress in Photovoltaics

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Polysilicon contact structures with ultra‐thin atomic layer deposited (ALD) oxide and nitride interlayers based on SiOx, SiNx, AlOx, AlNx, and TiOx either as part of an interlayer stack when applied on top of a conventional thermally‐grown SiOx or as a single interlayer were investigated. ALD SiOx single interlayers provided a very good passivation quality with high implied open‐circuit voltage and low‐specific contact resistivity when an optimal thickness and annealing temperature was applied. Also, ALD SiNx single interlayers showed a promising passivation quality, while AlOx and AlNx interlayers only allowed for a moderate and TiOx interlayers exhibited a very poor passivation quality. ALD SiOx interlayers on planar and textured silicon solar cells with poly‐Si(p) hole‐selective contacts and poly‐Si(n) electron‐selective contacts enabled a conversion efficiency of almost 21% as a proof‐of‐concept. These results are comparable with silicon solar cells with conventional thermally‐grown SiOx, showing that ALD SiOx interlayers are an alternative to conventional thermally‐grown SiOx in polysilicon contacts structures.

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“…In 2020, M. Lozac'h's group fabricated the tunnel oxide using a lab-scale remote-plasma plasma-enhanced ALD (PEALD). However, their reported cell V oc < 640 mV and cell efficiency < 19% were not remarkable by current standards [34,35]. Therefore, ALD was not considered a potential method for tunnel oxide fabrication in TOPCon solar cells as, for example, evidenced by review articles by D. Yan [22] and S. W. Glunz [36] published in 2021.…”

Section: Introductionmentioning

confidence: 99%

Atomic scale controlled tunnel oxide enabled by a novel industrial tube‐based PEALD technology with demonstrated commercial TOPCon cell efficiencies > 24%

Liao

Yeo

et al. 2022

Progress in Photovoltaics

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In this work, we report on a significant breakthrough in fabricating the critical tunnel oxide layer of tunnel oxide passivated contacts (TOPCon) high-efficiency solar cells compatible with high-volume manufacturing. We show that the tunnel oxide can be controlled at the atomic scale, enabled by an innovative tube-type industrial plasmaassisted atomic layer deposition (PEALD) method. In combination with an in situ doped poly-Si (n + ) layer grown by plasma-enhanced chemical vapor deposition, a uniform, ultrathin $1.3 nm SiO x layer is obtained at the c-Si/SiO x /poly-Si (n + ) interface.Extremely low recombination current densities down to 2.8 fA/cm 2 and an implied open-circuit voltage (iV oc ) as high as 759 mV are achieved, comparable to state-ofthe-art laboratory results. The developed tube-type PEALD SiO x is applied to industrial TOPCon solar cells resulting in a solar cell efficiency and open-circuit voltage of up to 24.2% and 710 mV, respectively. The tunnel oxide process window is about 2.4 Å, highlighting the importance of precisely controlling the tunnel oxide thickness at the atomic scale for TOPCon solar cells. The newly developed tube-type industrial PEALD SiO x method opens up a promising new route toward mass production of high-efficiency industrial TOPCon solar cells. Furthermore, the developed tube-type PEALD method can easily be integrated with the industrial tube-type plasmaenhanced chemical vapor deposition (PECVD) method, thus enabling the deposition of all thin film layers in TOPCon solar cells in one integrated PEALD/PECVD system. This significantly simplifies manufacturing complexity and fosters the commercialization of next-generation high-efficiency industrial TOPCon solar cells.

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Role of silicon surface, polished 〈100〉 and 〈111〉 or textured, on the efficiency of double‐sided TOPCon solar cells

Cited by 28 publications

References 56 publications

Influence of Silicon Substrate Surface Finish on the Screen‐Printed Silver Metallization of Polysilicon‐Based Passivating Contacts

Influence of Silicon Substrate Surface Finish on the Screen‐Printed Silver Metallization of Polysilicon‐Based Passivating Contacts

Polysilicon contact structures for silicon solar cells using atomic layer deposited oxides and nitrides as ultra‐thin dielectric interlayers

Atomic scale controlled tunnel oxide enabled by a novel industrial tube‐based PEALD technology with demonstrated commercial TOPCon cell efficiencies > 24%

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