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Processing in the Copper Indium Gallium Diselenide Cluster Tool

This page provides additional details on processing in the Copper Indium Gallium Diselenide (CIGS) cluster tool.

Wet-Chemistry Deposition

The wet-chemistry deposition tool will deposit buffer layers—most commonly CdS—for CIGS solar cells. This technique has been used to make record-efficiency CIGS devices, largely because in the solution, cadmium diffuses into the surface of the CIGS layer, forming an n-type buried homojunction.

In the conventional CIGS solar cell deposition process, this wet process requires a vacuum break and exposure to ambient humidity. But in this wet-chemistry deposition tool, bath deposition and transfer to and from the ultra-high vacuum will be performed completely in a controlled inert atmosphere, which preserves pristine surfaces never before possible in CIGS device processing. A CdS radiofrequency sputtering chamber for a dry window-layer deposition process complements this tool.

This deposition tool can also be used with alternative buffer layers, such as ZnS and InS. Combining this feature with its capabilities for in-situ monitoring, this tool greatly enhances current industry capabilities to research the performance and properties of CdS replacements. This chamber will also help researchers to investigate techniques to minimize the chemical bath's essential waste.


  • Depositing window layers—namely, CdS and CdS replacements and other window materials such as ZnS and InS

Special features:

  • Can heat substrate from room temperature to 85°C (independent of solution)
  • Can deposit layers as thin as 500 Å (0.05 µm)
  • In-situ real-time thickness monitoring that is based on reflection
  • Controlled ambient, inert atmosphere at atmospheric pressure
  • Little waste (<500 mL) per deposition

For more information, contact Ingrid Repins.