Fraunhofer Center for Silicon Photovoltaics CSP
Fraunhofer Center for Silicon Photovoltaics CSP

c-Si Defect Diagnostics from Module to Atom

UHV chamber of the ToF-SIMS
© Fraunhofer CSP
In the UHV chamber of the ToF-SIMS the chemical composition of a sample is determined with the aid of ion-sputtering sources.

We offer comprehensive structural analytics for our customers from the silicon photovoltaics sector. We are able to analyze all components along the value creation chain, i.e. from the manufacture of solar cells to the module, with regard to their structure and chemical composition macroscopically and microscopically down to the nanometer range. The results of the analyses are available to our customers for a rapid evaluation of materials and quality. On this basis, defect diagnosis, another of our key competences, produces precise details about the properties of defects, material aging and failure - in case of complex issues all the way to atomic resolution. With our customers, we further develop successfully accelerated laboratory methods and industrially applicable test instruments

We support our customers with simple service provisions as well as more comprehensive diagnostic problem solutions.

Services

  • High-resolution microstructure determination concerning structural arrangement and composition
  • Process-related structural analytics
  • Defect diagnostics in silicon photovoltaics
  • Development of test methods

Examples

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Prototype of PID solar cell tester
© Fraunhofer CSP
Prototype of PID solar cell tester.

Accelerated Test Procedure: PID Solar Cell Test

We developed a PID test which does not need the laborious manufacture of composite modules and climate chambers. The solar cells to be tested are exposed to high-voltage stress by means of an electrode. This rapid test method, for which a patent application has already been submitted, enables - next to a purely quantitative PID test - an easy preparation of degraded solar cell surfaces, necessary for the analytical examination of the various PID mechanisms.

back contact of a PERC solar cell
© Fraunhofer CSP
Quantitative assessment of defects of the back contact of a PERC solar cell.

Failure Diagnostics

If solar modules or solar cells display fault patterns their causes will often be retraceable to microscopically small structures. Production-oriented methods of quality control are suited only to a limited extent to identify them. Over a closed analytical chain to achieve an exact localization and characterization of solar modules to the microscopically small structure of a representative position, the c-Si Defect Diagnostics team takes over from the production-related methods. We search for specific causes and make customized proposals for solutions to avoid defects. A distinct advantage ensues from structural-chemical, electrical and thermal evaluation, which may merge correlatively, i.e. for exactly one and the same measurement position, in a complete characterization.

TEM analysis of functional layers
© Fraunhofer CSP
Thanks to the high-resolution TEM analysis, functional layers can be assessed and the defects be identified.

Ultra-high Resolution Analytics  

New and innovative solar cell concepts or module materials permit distinctive efficiency and quality enhancements by means of microstructured areas (as in PERC solar cells) or functionalized thin films. We apply modern preparation and high-resolution analytical methods to characterize and assess small structures. They give us information about local structural, chemical and electrical properties. With it, we support our customers in research and development, quality assurance, and in the identification of potential and existing faults and defects. Acting in close cooperation, we also develop and optimize customer-specific methods and solutions.