Publications by Franz-Josef Haug

Co-annealing of PECVD boron emitters and poly-Si passivating contacts for leaner TOPCon solar cell fabrication

Christophe Ballif, Franz-Josef Haug, Julien Hurni, Ezgi Genç, Sofia Libraro

This study investigates the feasibility of a single-step annealing process for tunnel oxide passivating contact (TOPCon) solar cell fabrication to replace the conventional two-step approach. We present a novel method using a single thermal treatment to sim ...

2025

nc-SiC by PECVD for High-Temperature Passivating Contacts

Christophe Ballif, Franz-Josef Haug, Julien Hurni, Ezgi Genç

Institute of Electrical and Electronics Engineers (IEEE)2025

Boron-emitter development for TOPCon c-Si solar cells based on plasma-deposited boron diffusion source and poly-Si(n) passivating contact

Christophe Ballif, Franz-Josef Haug, Julien Hurni, Ezgi Genç

The n-type TOPCon technology is currently the leading approach in the industry. Generally, it involves two high-temperature steps that can result in long cycle times and expensive processes. In this context, we propose a lean manufacturing process based on ...

2025

Impact of Rapid Thermal Processing on Bulk Lifetime and Surface Recombination Velocity of Crystalline Silicon With Passivating Tunnel Oxide Contacts

Christophe Ballif, Franz-Josef Haug, Julien Hurni, Ezgi Genç, Sofia Libraro, Audrey Marie Isabelle Morisset

We investigate rapid thermal processing (RTP) as alternative to the prolonged thermal annealing process used to form tunnel-oxide passivating contacts for silicon solar cells. The thermal treatment is generally followed by hydrogenation to passivate defect ...

Wiley2025

Hole-Selective SiNx and AlOx Tunnel Nanolayers for Improved Polysilicon Passivating Contacts

Franz-Josef Haug, Ezgi Genç, Sofia Libraro, Audrey Marie Isabelle Morisset

A highly efficient hole-selective passivating contact remains the crucial step required to increase the efficiency of polysilicon-based Si solar cells. The future development of solar modules depends on a device structure that can complement the electron-s ...

2024

Development and characterization of N2O-plasma oxide layers for high-temperature p-type passivating contacts in silicon solar cells

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Julien Hurni, Ezgi Genç, Sofia Libraro, Audrey Marie Isabelle Morisset, David Fernando Reyes Vasquez

Full-area passivating contacts based on SiOx/poly-Si stacks are key for the new generation of industrial silicon solar cells substituting the passivated emitter and rear cell (PERC) technology. Demonstrating a potential efficiency increase of 1 to 2% compa ...

American Chemical Society (ACS)2024

Interactions between aluminium and fired passivating contacts during fire-through metallization (vol 249, 112051, 2023)

Christophe Ballif, Aïcha Hessler-Wyser, Antoine Descoeudres, Franz-Josef Haug, Mario Joe Lehmann, Andrea Ingenito, Sofia Libraro

Elsevier2024

Understanding and mitigating resistive losses in fired passivating contacts: role of the interfaces and optimization of the thermal budget

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Luca Massimiliano Antognini, Julien Hurni, Ezgi Genç, Sofia Libraro, Audrey Marie Isabelle Morisset

This work presents a study of p-type passivating contacts based on SiCx formed via a rapid thermal processing (RTP) step, using conditions compatible with the firing used to sinter screen-printed metallization pastes in industry. The contributions of the t ...

Elsevier2023

Passivating contact-based tunnel junction Si solar cells using machine learning for tandem cell applications

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Audrey Marie Isabelle Morisset, Hyunjung Park

Tandem solar cells are a key technology for exceeding the theoretical efficiency limit of single-junction cells. One of the most promising combinations is the silicon-perovskite tandem cells, considering their potential for high efficiency, fabrication on ...

ELSEVIER2023

Carrier generation and collection in Zn3P2/InP heterojunction solar cells

Anna Fontcuberta i Morral, Franz-Josef Haug, Mahdi Zamani, Simon Robert Escobar Steinvall, Julien Hurni, Rajrupa Paul, Valerio Piazza, Mirjana Dimitrievska, Joel René Sapera

Zinc phosphide (Zn3P2) has been lauded as a promising solar absorber material due to its functional properties and the abundance of zinc and phosphorous. In the last 4 decades, there has not been any significant improvement in the efficiencies of Zn3P2-bas ...

ELSEVIER2023

Pre-annealing for improved LPCVD deposited boron-doped poly-Si hole-selective contacts

Xinyu Zhang, Franz-Josef Haug, Luca Massimiliano Antognini, Zhao Wang, Jie Yang, Josua Andreas Stückelberger

We demonstrate the beneficial effect of a pre-annealing step prior to the boron diffusion on passivation and contact resistivity of industrially LPCVD deposited poly-Si/SiOX hole-selective contacts. We investigate the influence of the pre-annealing tempera ...

ELSEVIER2023

Interactions between aluminium and fired passivating contacts during fire-through metallization

Christophe Ballif, Aïcha Hessler-Wyser, Franz-Josef Haug, Mario Joe Lehmann, Sofia Libraro

Replacing silver metallization with earth-abundant materials in Si solar cells is a critical step towards the sustainable growth of photovoltaics. In this work, we investigate fire-through processes using Al for the metallization of solar cells with p-type ...

ELSEVIER2023

Bandgap engineering of indium gallium nitride layers grown by plasma-enhanced chemical vapor deposition

Christophe Ballif, Aïcha Hessler-Wyser, Nicolas Würsch, Franz-Josef Haug, Mathieu Gérard Boccard, Jonathan Emanuel Thomet

This paper reports on the fabrication of In xGa 1 - xN (InGaN) layers with various compositions ranging from InN to GaN using a cost-effective low-temperature plasma-enhanced chemical vapor deposition (PECVD) method and analyzes the influence of deposition ...

2022

In Situ Reflectometry and Diffraction Investigation of the Multiscale Structure of p-Type Polysilicon Passivating Contacts for c-Si Solar Cells

Christophe Ballif, Franz-Josef Haug, Andrea Ingenito, Audrey Marie Isabelle Morisset

The integration of passivating contacts based on a highly doped polycrystalline silicon (poly-Si) layer on top of a thin silicon oxide (SiOx) layer has been identified as the next step to further increase the conversion efficiency of current mainstream cry ...

AMER CHEMICAL SOC2022

Bulk Defects and Hydrogenation Kinetics in Crystalline Silicon Solar Cells With Fired Passivating Contacts

Christophe Ballif, Philippe Wyss, Franz-Josef Haug, Mario Joe Lehmann, Père Roca i Cabarrocas, Andrea Ingenito, Audrey Marie Isabelle Morisset

In this article, the effect of the various processing steps during the fabrication of c-Si/SiOx/SiCx fired passivating contacts on the silicon bulk lifetime is studied, and the kinetics of defect deactivation by hydrogenation is investigated. It is found t ...

2022

Status and perspectives of crystalline silicon photovoltaics in research and industry

Christophe Ballif, Franz-Josef Haug, Mathieu Gérard Boccard

Crystalline silicon (c-Si) photovoltaics has long been considered energy intensive and costly. Over the past decades, spectacular improvements along the manufacturing chain have made c-Si a low-cost source of electricity that can no longer be ignored. Over ...

2022

Localisation of front side passivating contacts for direct metallisation of high-efficiency c-Si solar cells

Christophe Ballif, Sylvain Nicolay, Xavier Niquille, Franz-Josef Haug, Frank Meyer, Andrea Ingenito

In this work, we present the development of passivating contacts based on thin interfacial oxide/doped polysilicon for two side contacted c-Si solar cells. In the first part, we discuss our layer optimization towards direct metallisation, using firing thro ...

ELSEVIER2022

Impact of rapid thermal processing on bulk and surface recombination mechanisms in FZ silicon with fired passivating contacts

Christophe Ballif, Franz-Josef Haug, Mario Joe Lehmann, Andrea Ingenito, Sofia Libraro, Audrey Marie Isabelle Morisset

We investigate bulk and interface recombination in crystalline silicon with p-type fired passivating contacts. These consist of a chemical oxide and an in-situ doped layer of SiCx with low carbon content. Following a rapid thermal annealing to activate the ...

ELSEVIER2022

Nanoscale Study of the Hole-Selective Passivating Contacts with High Thermal Budget Using C-AFM Tomography

Christophe Ballif, Quentin Thomas Jeangros, Franz-Josef Haug, Gizem Nogay, Martin Ledinsky, Philipp Friedrich Hermann Löper

We investigate hole-selective passivating contacts that consist of an interfacial layer of silicon oxide (SiOx) and a layer of boron-doped SiCx(p). The fabrication process of these contacts involves an annealing step at temperatures above 750 degrees C whi ...

AMER CHEMICAL SOC2021

Evaluation of secondary electron intensities for dopant profiling in ion implanted semiconductors: a correlative study combining SE, SIMS and ECV methods

Aïcha Hessler-Wyser, Quentin Thomas Jeangros, Philippe Wyss, Franz-Josef Haug, Mario Joe Lehmann, Audrey Marie Isabelle Morisset

This study evaluates the secondary electron (SE) dopant contrast in scanning electron microscopy (SEM) and helium ion microscopy (HIM) on boron implanted silicon sample. Complementary techniques like secondary ion mass spectrometry and electrochemical capa ...

IOP PUBLISHING LTD2021