Laurent Clochard

Laurent Clochard
Nines Photovoltaics · R&D

Master of Science

About

29
Publications
2,782
Reads
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144
Citations
Introduction
Dry etching process and equipment development for silicon etching. Atmospheric process (AP) developments for Solar cells, sensors, battery, and other industrial applications.
Education
September 1998 - September 2000
Trinity College Dublin
Field of study
  • Physics
September 1996 - September 1997
University of Grenoble
Field of study
  • Physics
September 1993 - September 1996
La Rochelle Université
Field of study
  • Physics

Publications

Publications (29)
Article
In this article, we present an optimization of the emitter diffusion for nanotextured p-type monocrystalline silicon solar cells using atmospheric pressure dry etching (ADE) in conjunction with a post-ADE short acidic etch in a passivated emitter and rear cell (PERC) architecture. The optimization of the phosphorus oxychloride diffusion process was...
Article
Full-text available
Single-sided etching (SSE) of a-Si/poly-Si is typically considered a challenge for realizing a cost–efficient TOPCon production sequence, as there is a certain degree of unwanted wrap–around for various poly-Si deposition technologies such as LPCVD, PECVD and APCVD. To date, alkaline or acidic wet-chemical solutions in either inline or batch config...
Article
Full-text available
In this paper, we study the plasma-less etching of crystalline silicon (c-Si) by F2/N2 gas mixture at moderately elevated temperatures. The etching is performed in an inline etching tool, which is specifically developed to lower costs for products needing a high volume manufacturing etching platform such as silicon photovoltaics. Specifically, the...
Conference Paper
Full-text available
In this work, we investigate the emitter sheet resistance and emitter recombination current density by optimizing the POCl3 emitter diffusion process parameters to achieve improved electrical properties and cell performance. Wafers used in the experiment were boron-doped p-type mono-crystalline silicon samples, nanotextured in an atmospheric pressu...
Conference Paper
Full-text available
In this work, we investigate the electrical performance of multicrystalline silicon (mc-Si) solar cell precursors in terms of minority charge carrier lifetime and implied open-circuit voltage as a function of the different surface passivation layers applied. Here, we applied a plasma-less nanotexturing process by atmospheric pressure dry etching (A...
Patent
The invention relates to a method for etching silicon wafers, comprising the treating the silicon wafer with an HF-containing gas mixture and F2-containing gas. The invention also relates to an etched silicon wafer that can be produced by said method. The invention further relates to an HF-containing gas mixture for pretreating silicon wafers befor...
Conference Paper
Full-text available
In this work, we investigate the emitter performance of the multicrystalline silicon (mc-Si) solar cell as a function of the crystallographic orientation of the grains and the associated texturing level. Here, we applied a plasma-less nanotexturing process by atmospheric pressure dry etching that enables low reflectivity, followed by a short anisot...
Conference Paper
Full-text available
In this paper, we present further results on the integration of a "black-silicon" texturing process on diamond-wire sawn multicrystalline silicon wafer, using atmospheric pressure dry texturing (ADE) in a passivated emitter and rear cell (PERC) solar cell architecture. Following on from our previous work on high-efficiency nanotextured solar cells,...
Article
Improving the texturing approach for diamond wire-sawn (DWS) multicrystalline silicon (mc-Si) wafers is one of the key steps to decrease its efficiency gap to monocrystalline silicon-based solar cells. In this regard, black silicon texturing has increasingly caught attention of both academia and industries as a potential approach towards mass produ...
Conference Paper
Full-text available
In this paper, we report significant progress in development and integration of a plasma-less atmospheric pressure dry texturing (ADE) process, performed on multicrystalline silicon (mc-Si) wafers, into high efficiency PERC solar cell architectures using industrially applied process steps. The mechanism of forming sub-micron features on monocrystal...
Poster
Full-text available
ADE Dry Texturing + PERC mc-Si wafers reaches 20.3% efficiency (+0.2% abs. uplift) without any process tuning, paving the way for diamond wire cut mc-Si texturing.
Article
Full-text available
In this contribution, atmospheric pressure dry etching (ADE) texture is integrated into a passivated emitter and rear cell (PERC) process. In order to make the texture suitable for the solar cell processing, two post-etching processes (inverted pyramid, spherical cap) are implemented and compared. The passivation of the front surface could be impro...
Article
In this paper, we study the impact of change in emitter diffusion profiles on the electrical characteristics of nanotextured surfaces formed by an inline plasma-less dry-chemical etching process. Our experimental results and process simulations suggest that a deeper highly doped region and a significantly higher inactive P concentration in the emit...
Article
In this paper, we study the effect of an enlarged surface area of nanotextured crystalline silicon wafers on the formation of n-type emitters using a tube diffusion process applying POCl3 as P dopant source. A fast, single-step and industrially viable F2-based dry texturing process is used to perform nanotexturing of Si wafers. This process is pres...
Article
Full-text available
In this paper, we study the influence of modifying the geometry of nanotexture on its electrical properties. Nanotexture is formed by an industrially feasible dry-chemical etching process performed entirely in atmospheric pressure conditions. A surface modification process is developed that allows low surface recombination velocities (Seff,min ? 10...
Article
We report recent achievements in adapting industrially used solar cell processes on nanotextured surfaces. Nanostructures were etched into c-Si surfaces by dry exothermic plasma-less reaction of F species with Si in atmospheric pressure conditions and then modified using a short post-etching process. Nanotextured multicrystalline wafers are used to...
Article
A novel atmospheric pressure dry texture process is investigated in order to create nanostructures at the c-Si surface. The texture process uses diluted molecular fluorine (F2) as the process gas. F2 is partially dissociated at an elevated temperature before it is delivered to the c-Si wafer. Thermal activation of fluorine occurs on Si wafer surfac...
Conference Paper
Full-text available
Reduction of surface reflection remains a key area of investigation in order to improve the light confinement of solar cells. Our one step atmospheric pressure dry etching process uses F 2 gas to form nanotextures of different aspect ratios on c-Si surfaces. The developed process is expected to be economically competitive with wet-chemical texturin...
Conference Paper
Full-text available
As an alternative to the current wet-chemical etching, used in crystalline solar silicon industry, Fraunhofer IWS in collaboration with Nines PV and Fraunhofer ISE developed a dry-chemical etching technology at atmospheric pressure using elemental Fluorine (F ) as etching gas. Process control plays an important role when aiming at industrialization...
Patent
The invention relates to a process for dry chemical texturing of a substrate. More particularly, the invention relates to a process for a combined dry chemical etching and passivation of a substrate (for example, silicon-based photovoltaic (PV) devices).
Conference Paper
Full-text available
The front texture of crystalline silicon solar cells plays a crucial role in order to effectively harvest light and transform it into electricity. In this paper, a novel technology based on dry atmospheric pressure etching is presented. It allows the single-sided inline etching of c-Si wafers using the global warming potential-free process gas fluo...
Patent
A method and apparatus to modify the surface structure of a silicon substrate or deposited silicon layer in a controllable manner using gas only, suitable for making photovoltaic (PV) devices, the method and apparatus comprising the steps of disposing the substrate or deposited layer on a moveable carrier; pre-heating the substrate or deposited lay...
Conference Paper
Permanent magnet based FTICR instruments have a minimized size and weight, and do not require cryogenic fluid, making them easily transportable instruments. Typically, the maximum field available in a 50mm diameter bore permanent magnet is smaller than 1.3T and the field homogeneity explored by the ions is about to 10-3. We will compare several des...
Article
Permanent magnet field sources made of NdFeB, in particular the Halbach cylinders, have not previously been used by rock magneticists. Here, their use is explored for determining saturation IRM (SIRM) and S ratio. An original “one-step” scheme is presented to obtain both parameters in one measurement and one operation of IRM acquisition using two c...

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Cited By

Projects

Projects (3)
Project
Removal of the poly-Si wrap around is critical for delivering reliable TOPCON cells and modules. For back contact passivation, the poly-Si layer needs to be on the rear side of the cell. Most deposition techniques lead to some degree of undesired wrap around, resulting in poly-Si at the front of the wafer, located around the edges or covering the full face. The poly-Si needs to be removed not only from the front surface but also from the edges of the wafers in order to avoid any shunting, that could lead to irreversible damages once the cell is operated in a module. Atmospheric Dry Etching (ADE) is well suited to this removal task, being single sided. The ADE process is an in-line chemical vapor etch process, carried out at atmospheric pressure (AP). Contrary to traditional "dry etch", the ADE equipment has no vacuum pumps, nor does it require plasma. It uses a thermally induced chemical reactions at the surface of a heated wafer, with reagents supplied in gaseous form. This project will apply the ADE process to the etching requirements of TOPCON solar cell architectures.
Project
This project consists in the setup of a new fully automated pilot line in order to be able to texture diamond wire cut wafers at high throughput, using the ADE process (Atmospheric Dry Etching), a plasma-less and vacuum less method that can deliver high trhoughput at low cost of ownership for solar cell manufacturing.