Front and rear silicon‐nitride‐passivated multicrystalline silicon solar cells with an efficiency of 18.1%

Mittelstädt, L.; Dauwe, S.; Metz, A.; Hezel, Rudolf; Hässler, C

doi:10.1002/pip.423

Cited by 16 publications

(8 citation statements)

References 3 publications

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“…[6][7][8][9][10][11][12][13][14][15][16] Now that surface passivation using silicon nitride can be made as good as that using a thermal oxide, the material is increasingly used for the fabrication of high-efficiency silicon solar cells. [17][18][19] Big advantages of silicon nitride grown by PECVD with respect to thermal oxide are the low process temperature (typically in the range 300-400 C) and the short process time (typically a few minutes). The low process temperature is particularly important in the case of mc-Si wafers, where high-temperature processing, like thermal oxidation, may cause severe degradation of the bulk lifetime of charge carriers.…”

Section: Introductionmentioning

confidence: 99%

Bulk and surface passivation of silicon solar cells accomplished by silicon nitride deposited on industrial scale by microwave PECVD

Soppe

Rieffe

Weeber

2005

Prog. Photovolt: Res. Appl.

135

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Bulk and surface passivation by silicon nitride has become an indispensable element in industrial production of multicrystalline silicon (mc-Si) solar cells. Microwave PECVD is a very effective method for high-throughput deposition of silicon nitride layers with the required properties for bulk and surface passivation. In this paper an analysis is presented of the relation between deposition parameters of microwave PECVD and material properties of silicon nitride. By tuning the process conditions (substrate temperature, gas flows, working pressure) we have been able to fabricate silicon nitride layers which fulfill almost ideally the four major requirements for mcSi solar cells: (1) good anti-reflection coating (refractive index tunable between 2Á0 and 2Á3); (2) good surface passivation on p-type FZ wafers (S eff < 30 cm/s); (3) good bulk passivation (improvement of IQE at 1000 nm by 30% after short thermal anneal); (4) long-term stability (no observable degradation after several years of exposure to sunlight). By implementing this silicon nitride deposition in an inline production process of mc-Si solar cells we have been able to produce cells with an efficiency of 16Á5%.Finally, we established that the continuous deposition process could be maintained for at least 20 h without interruption for maintenance. On this timescale we did not observe any significant changes in layer properties or cell properties. This shows the robustness of microwave PECVD for industrial production.

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Section: Introductionmentioning

confidence: 99%

Bulk and surface passivation of silicon solar cells accomplished by silicon nitride deposited on industrial scale by microwave PECVD

Soppe

Rieffe

Weeber

2005

Prog. Photovolt: Res. Appl.

135

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“…The reason for the FF improvement is still under investigation, however a possible explanation to this increase is the impact of the injection dependence of ideality factor in the voltage range between MPP and opencircuit conditions. It was suggested in 2-D simulations [6] that a higher positive insulator charge density (for example, using our 200°C deposited SiO x film) in combination with an LBSF (instead of a standard ohmic contact) can improve the cell J sc by ∼1.7 mA/cm 2 . However, this was not observed in this study, as no change in J sc was observed.…”

Section: B Aluminum Local Back Surface Field Solar Cell Resultsmentioning

confidence: 97%

“…Hence, it was demonstrated back then that the positive charge in the rear dielectric film does not detrimentally affect the Al-LBSF solar cell efficiency when a local BSF exists underneath the metal contacts. In fact, from 2-D simulation and experiments it seems that a higher positive insulator charge density can even improve the efficiency of Al-LBSF cells, by improving the short-circuit current density J sc [6], [7]. In contrast, it is often mentioned that SiN x can lead to compromised solar cell efficiency when applied on the rear of p-type Si solar cells with local rear contacts; see, e.g., [8].…”

Section: Introductionmentioning

confidence: 99%

Dielectric Charge Tailoring in PECVD SiO<inline-formula> <tex-math>${}_x$</tex-math> </inline-formula>/SiN <inline-formula> <tex-math>${}_x$</tex-math> </inline-formula> Stacks and Application at the Rear of Al Local Back Surface Field Si Wafer Solar Cells

Duttagupta

Hameiri

Grosse

et al. 2015

IEEE J. Photovoltaics

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State-of-the-art surface passivation results are obtained on undiffused p-type commercial-grade Czochralski Si wafers with effective surface recombination velocity S eff values of ∼8 cm/s and implied open-circuit voltage iV o c values of up to 715 mV with an industrially fired dielectric stack of silicon oxide and silicon nitride (SiO x /SiN x ) deposited in an industrial inline plasma-enhanced chemical vapor deposition reactor.We are able to controllably vary the total positive charge density Q to tal in the stack by more than one order of magnitude (10 11 -10 12 cm −2 ) with no impact on midgap interface state density D it,m idgap (5 × 10 11 eV −1 ·cm −2 ) by altering the deposition temperature of the SiO x layer in the stack. We show experimentally that, for inversion conditions, S eff scales with the inverse square of the charge density 1/Q 2 to tal , which is in good agreement with theory. Based on the measured injection-level-dependent minority carrier lifetimes and the total positive charge densities, it is shown that films with higher positive charge density have higher 1-sun V o c and fill factor (FF) potential. Large-area alloyed aluminum local back surface field solar cells confirmed this by showing higher conversion efficiency by 0.17% absolute due to improved cell V o c and FF of the solar cells featuring a SiO x /SiN x stack with a higher Q to tal .Index Terms-Charge engineering, crystalline silicon, industrial firing, injection-level dependence, interface properties, lowtemperature surface passivation, SiO x /SiN x stacks. search Institute of Singapore, Singapore. His research interests include advanced fabrication and characterization of high-efficiency silicon wafer solar cells.

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“…A thin layer of aluminum was deposited at the front surface; the thickness was measured by thickness monitor Edward's FTM5, followed by evaporation of thick layers of aluminum and silver through a mechanical mask to form the front contact grid [12][13][14][15][16]. In the present work we used an optimized MIS mc-Si film which reduces parasitic shunting, thus the formation of the local Al-BSF could be omitted.…”

Section: Experimental Workmentioning

confidence: 99%

“…As E p increases above E g , more and more electrons from the valence band can possibly make the transition, so the overall probability of a photon being absorbed increases. Thus, the number of photons absorbed increases [12,13].…”

Section: Fig 1 Large-grains Mc-si Thin Filmmentioning

confidence: 99%

Study of Mis Multicrysraline Silicon Thin-Film Solar Cell

El-Amin

Hassan

2008

JES. Journal of Engineering Sciences

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State-of-the-art of multicrystalline Silicon (mc-Si) material with minority carrier diffusion lengths exceeding the wafer thickness is commercially available today. It is expected that the diffusion length to wafer thickness ratio will be increasing further due to improved material quality and due to the trend towards thinner wafers to reduce material costs. As a result, the open circuit voltage, V oc decreases with increasing temperature according the ratio V oc /T = 0.00337 mVK-1. The output power decrease with increasing temperature mainly because of a decrease in the photovoltaic and fill factor of the current voltage characteristic. This happens in samples which have P /T =  0.00048 WK-1 , FF / T = 0.002 %K-1 , and R / T =  0.021  K-1. In order to fully exploit the material quality, a solar cell process that includes excellent rear surface passivity is needed. In this paper solar cell results from thin mc-Si solar cells with silicon nitride front and rear surface passivity are presented. Furthermore, the most important loss mechanisms with respect to thin mc-Si cells namely : (i) optical losses, (ii) losses due to rear surface recombination and (iii) losses due to the series resistance caused by local rear contact schemes with dielectric passivity are discussed. The light trapping effect of this structure is also confirmed reflection at the weakly absorbed wavelength.

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Front and rear silicon‐nitride‐passivated multicrystalline silicon solar cells with an efficiency of 18.1%

Cited by 16 publications

References 3 publications

Bulk and surface passivation of silicon solar cells accomplished by silicon nitride deposited on industrial scale by microwave PECVD

Bulk and surface passivation of silicon solar cells accomplished by silicon nitride deposited on industrial scale by microwave PECVD

Dielectric Charge Tailoring in PECVD SiO<inline-formula> <tex-math>${}_x$</tex-math> </inline-formula>/SiN <inline-formula> <tex-math>${}_x$</tex-math> </inline-formula> Stacks and Application at the Rear of Al Local Back Surface Field Si Wafer Solar Cells

Study of Mis Multicrysraline Silicon Thin-Film Solar Cell

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