Evaluation of Spatial ALD Al2O3 versus PECVD for rear surface passivation of multi cSi solar cells
This article shows the evaluation results on industrial p-type mc-Si PERC cells using spatial atomic layer deposition for aluminum oxide from SoLayTec. By optimizing the process flow and integrating a post-deposition anneal into the SiNx capping process we achieve 0.15% higher cell efficiency compared to remote microwave plasma-enhanced chemical vapor deposition. If the FF were to be improved for ALD PERC cells, then these cells could reach 0.25% efficiency gain with respect to MW-PECVD. Furthermore, it is shown that the improved passivation quality resulting in Voc gain remains constant during light and elevated temperature induced degradation measurements.
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Al2O3 Passivation for Copper Plated IBC Cells 15.6x15.6 cm2
Today, the silicon solar cells with the highest efficiency are interdigitated back contact solar cells. At imec, the cell concept for 15.6x15.6 cm2 IBC cells relies on a rear design with multiple busbars and a Cu plated rear metallization. Previously, we reported efficiencies up to 21.9% by introducing Cu plated contacts. Further developments in the rear design to overcome FF and Jsc losses were implemented and reported as well, showing IBC cells with 22.5% efficiency. In a subsequent optimization round, the passivation quality at the rear of these IBC cells needed to be improved. To do so, we demonstrate in this paper the application of a rear Al2O3 based passivation stack on both emitter and BSF.
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Upgrade of an Industrial Al-BSF solar cell line into PERC using spatial ALD Al2O3
In this paper, we report the results of an upgrade from an Al-BSF solar cell line to a PERC (passivated emitter and rear cell) solar cell line, based on p-type mono-crystalline silicon (mono c-Si) material. For the rear side Al2O3 passivation, an InPassion ALD system of SoLayTec was used. The PERC solar cell optimization has been done in three main steps: first we optimized the rear ...
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Bifacial n-PERT cells with Al2O3 and plated contacts for multi-wire interconnection
In this paper we introduce bifacial n-type PERT cells (Bi-PERT) with ultra-thin (< 3 um) and narrow (< 20 um) Ni/Ag plated fingers on both the n+ and p+ side of the cell. This cell architecture is designed for multi-wire interconnection and has the potential to deliver low Cost of Ownership at module level (< 0.40 $/Wp), as it can profit from bifacial gain, a low cost metallization sequence and the high efficiency potential of multi-wire interconnection.
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Translating 2nd Generation InPassion ALD into significant financial gains
The article is in both Chinese and English. Last December SoLayTec celebrated its 5th anniversary, and in the meantime has installed about twenty items of ALD equipment in the PV industry. We are happy to be the leading ALD supplier in this market. Unfortunately, while we are not yet number one in the market for Al2O3 passivation, we do expect to win further market share with our 2nd generation ALD system. As we all know, a successful product is based not only on the right timing of the market introduction but also on its uniqueness and user-friendliness. After installing machines at various PV manufacturers, we started to learn about the pros and cons of our system. In this article I would like to explore both these topics and convince you to become one of our next ALD users. "Published PES magazine edition PES Solar China issue 2016"
461 DownloadsPERC is hot. So think smart
It will not have escaped your attention that PERC is indeed setting the agenda right now. But to stay one step ahead, it’s worth ‘thinking smart, and choosing Spatial ALD’ argues SoLayTec’s Roger Görtzen in a typically passionate and well considered piece. "Published: PES magazine, edition 27 2015"
1792 DownloadsLarge Area N-Type c-SI solar cells featuring rear emitter and efficiency beyond 21%
We present large area n-type solar cells (n-PERT) featuring a rear-boron-diffused emitter passivated with a stack of ALD Al2O3 and PECVD SiOx. We present the advantages of such a device structure and we show that efficiencies of 22% are within reach in the near future even without resorting to a back-contacted configuration and/or contact passivation.
2653 DownloadsImplementation of an ALD Al2O3 PERC technology into multi and mono cSi
In this paper, we present the InPERC technology implemented into a multi- and monocrystalline silicon (mc- and Cz-Si) solar cell production of major Asian cell manufacturers. Stable average efficiencies over 18% and 20% respectively were demonstrated. Best average efficiencies of 18.4% were achieved on mc-Si solar cells with a best cell efficiency of 18.8%. To reduce the cost of ownership (CoO) of the InPERC upgrade, the annealing step after ALD of Al2O3 was successfully skipped by integrating it into the direct tube PECVD without increase of PECVD process time. Furthermore, the Al2O3 thickness was reduced to 4 nm and the etch removal for rear side smoothening to 2 μm without loss in efficiency. An InPERC module passed all applied accelerated ageing tests (five times humidity freeze, damp heat, PID-test). In a CoO-comparison of different PERC routes, the InPERC technology showed the lowest total CoO.
2289 DownloadsSpatial ALD of i-ZnO films for applications in the PV industry
Intrinsic as well as doped zinc oxide (ZnO) thin films are used in the photovoltaic industry as transparent and conducting window layers. The most common deposition technique for ZnO is sputtering which is known to cause near-surface damage due to the exposure of the underlying material to highly energetic ions. Atomic layer deposition (ALD) is a low-damage deposition technique that offers explicit control of film thickness and uniformity with self-limiting half-reactions, however, its main drawback is its low deposition rate. This limitation is overcome by the recently developed spatial ALD technique. In this work, intrinsic ZnO films are deposited in a commercial spatial ALD system for the first time and the optical and electrical film properties are analyzed in detail.
3277 DownloadsInfluence boron emitter profile Voc and Jsc losses ion implanted n-type PERT with SoLayTec Al2O3
Introduction: N-type PERT (passivated emitter and rear, totally doped) solar cells [1] with boron emitters have attracted recently significant research interest [2–6]. While the efficiencies reported so far for industrial n-type PERT cells are comparable to the respective values for as-processed p-type PERC (passivated emitter and rear cell) cells, the n-type base material does not suffer from light-induced degradation. While also back-junction n-PERT cells are investigated [7], most groups work on n-PERT cells with a front-side boron emitter. In order to contact the latter via screen-printing, as it is standard for industrial applications, special Ag/Al pastes seem to be required.
2878 Downloads