Coating Technologies and High-Temperature Processes

The surface quality of a solar cell significantly influences its efficiency potential. We are therefore working on various methods and technologies for passivation and the optimization of light trapping in silicon solar cells in the "Coating Technologies and High-temperature Processes" Research Topic. The focal points of our work include 

  •  Single and multilayer anti-reflective coatings 
  • Dopant precursors and multifunctional layers 
  • Passivation layers and layer systems 
  • Barrier layers 
  • Materials: among others: SiNx, SiOx, SiCx, Al2O3, a-Si (i/n/p), c-Si (i/n/p), ITO 
  • Deposition technologies: PECVD, LPCVD, PVD, ALD 

Solar cells require differently doped areas, e.g. the pn junction or »high-low junctions«, which fulfill different functions. In addition to the established method of tube diffusion used in photovoltaics, Fraunhofer ISE also has these other methods available for the realization of these full-surface or localized doping processes: 

  • Diffusion from dopants provided via the gas phase, currently POCl3 and BBr3 are available as sources at ISE 
  • Diffusion from deposited/printed and possibly structured layers in the tube furnace and in the continuous process 
  • Laser diffusion from deposited/printed layers and from the liquid phase, as well as laser transfer doping 
  • Thermal oxidation for post-treatment after doping processes, surface passivation and masking 

The aim of our research work is to develop ideal and tailor-made solutions for the realization of passivated and doped areas for the large number of different solar cell concepts. The main requirement here is to create physically perfect surfaces and interfaces as well as doping (metal-semiconductor contact, minimization of recombination, structure size, etc.) and to use methods that are both cost-effective and can be implemented with the throughput required for production


Fields of Work

In the research topic "Coating Technologies and High-Temperature Processes" we focus on the following fields of work:

Customized Processing Solutions

Development of Coating and Doping Processes

Process Integration of Novel Coating and Doping Techniques

Characterization of Thin, Functional Coatings and Dopings

R&D Services

We offer processing services for customized solutions and develop special coating and doping processes according to customer requirements. We offer process integration into existing process sequences for the production of high-efficiency solar cells. For laboratory cells, we have state-of-the-art clean room technology and laboratories in the "Center for High Efficiency Solar Cells" at our disposal. For large-area, industrial solar cells (M2 to M6) using production technologies, we use our industry-oriented production facilities and the infrastructure at the "PV Technology Evaluation Center PV-TEC". We have many years of experience in the characterization of thin, functional layers and doping and offer services relating to layer thickness, refractive indices, doping profile, charge carrier profile, recombination properties, etc.

R&D Infrastructure

This infrastructure is available to us at Fraunhofer ISE for our research and development activities:


Center for High Efficiency Solar Cells

Technologies for highest PV efficiency values


Photovoltaic Technology Evaluation Center


Production and Measurement Technology for Crystalline Silicon Solar Cells

Selected Research Projects



Record Efficiencies for Double-Sided Silicon Solar Cells and Pero-Pero-Si Triple-Junction Solar Cells



Linear Evaporation Processes for Large-Area Industrially Scalable Perovskite-Silicon Tandem Solar Cells



Technology Platform for Scaling Up Perovskite-Silicon Tandem Solar Cells and Modules