Fraunhofer Center for Silicon Photovoltaics CSP

Fraunhofer Center for Silicon Photovoltaics CSP

Ultratrace Analysis

ICP-MS — © Fraunhofer CSP
The ICP-MS is loaded with samples.

We offer our customers comprehensive analytical services of a wide range of materials down to the ultratrace range. In addition to the determination of total concentrations down to the low ppb range, methods for locally resolved analysis are also available. All methods are adapted to the special purity requirements of semiconductor materials. The development of adapted analytical methods, e.g. for process monitoring and quality control, as well as consulting and training on trace analysis are also part of our scope of services.

We offer standardized contract analyses as well as complex root cause investigations, from single orders to extensive research and development projects.

Our research facility is certified according to DIN ISO 9001.

Surface Purity

Surface purity Si-wafer — © Fraunhofer CSP
Impurities on wafer surfaces can be collected in an acidic extractant and subsequently quantified by ICP-MS.

Surface Extraction ICP-MS: Determination of elemental contents by ICP mass spectrometry after surface extraction
Adaptation of the etching solution to the customer's needs (e.g. surface only, surface incl. oxide layer, thick oxide layers, ...)
All wafer sizes are possible
Detection limits element dependent up to 1E7 atoms/cm²

High Purity Oligosilanes

hexachlorodisilane — © Fraunhofer CSP
Hexachlorodisilane (HCDS) is used as a precursor material for the production of very thin films and therefore requires a very high purity, which can be determined by ICP-MS.

Chemical vapor phase digestion of silanes (e.g. HCDS, PCDS, STC, TCS...) and subsequent trace element analysis by ICP-MS
Analysis of high purity materials as well as raw materials possible
Required sample quantity ideally 10 g
Detection limits element-dependent, in the range 5 ppt to 1 ppb

In the project "SilaTrace" we developed together with our partner PSC Polysilane Chemistry GmbH high purity pentachlordisilane as an attractive product for the microelectronics industry. At Fraunhofer CSP, the main focus was on the optimization of trace analysis to ensure product quality. This funding was financed by the European Regional Development Fund (ERDF).

Ultra Trace Analysis in Solids

Experimental CZ silicon crystal — © Fraunhofer CSP
Experimental CZ silicon crystal and vertical concentration profile of impurities (example: aluminum).

High purity of starting materials is the basic requirement for high-performance solar cells and semiconductor devices
Chemical digestion and subsequent determination of elemental contents by ICP mass spectrometry
Samples: Feedstock, crystals, wafers, dopants, powders....
Required sample material: ideally 5 g

Impurities in the crucible and coating determine the quality of the silicon crystal (publica.fraunhofer.de)
Influence of feedstock purity on solar cell quality (publica.fraunhofer.de)
Purification of metallurgical silicon by metal-assisted chemical etching (MaCE) (publica.fraunhofer.de)

High Purity Acids

High purity acids — © Fraunhofer CSP
High-purity acids are required for many applications. The trace element contents contained - often in the ppt range - can be detected by ICP-MS.

Trace element analysis in high purity solutions (e.g. high purity hydrofluoric acid, nitric acid...)
Dilutions or evaporation as sample preparation necessary
Sample volume min. 5 mL
Detection limits in the ppt range (element-dependent)
Detection limits depending on sample and element in the lower ppb to ppt range

Aequeous Solutions

Purity of aqueous solutions — © Fraunhofer CSP
The very high purity of aqueous solutions required for many processes can be checked using ICP-MS analysis.

Trace element analysis in aqueous solutions
Sample volume min. 5 mL
Detection limits in the lower ppt range (element-dependent)

Sequentiell Etching

Characterization of wafer surfaces — © Fraunhofer CSP
By using different acids in the etching process, the layers of materials can be analyzed separately.

Detection of surface contaminations, which also penetrate into deeper layers
Layer-specific etching and subsequent ICP-MS analysis can help determine where which contaminants are localized and how to efficiently clean them up
Samples: Wafers, chunks, granules, powders

Localization of inorganic impurities in silicon samples by sequential etching and ICP-MS detection, 6th International Conference on Silicon Photovoltaics, SiliconPV 2016 [ PDF 0.35 MB ]

Materials Resistance to Acids

Testing of various materials, e.g. polymers, sealing materials, etc., against the influence of acids
Variation of acids, acid concentrations and temperatures
Leaching: determination of elemental contents dissolved from the material by ICP-MS
Determination of sample geometries and microscopic changes before and after ageing tests
Measurement of stress-strain behavior according to common standards (e.g. DIN EN ISO 527-3) on treated and untreated samples

Consulting and Training on Trace Analysis

Training trace analysis — © Fraunhofer CSP
Book an on-site training under the professional guidance of our staff.

We offer consulting services on the subject of trace analysis, assistance in setting up your own trace analysis laboratory, and on-site training for your employees.