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Copper Indium Gallium Diselenide Cluster Tool Capabilities

The Copper Indium Gallium Diselenide (CIGS) cluster tool in the Process Development and Integration Laboratory offers powerful capabilities with integrated chambers for depositing, processing, measuring, and characterizing photovoltaic materials and devices. You can read more on the rationale for developing this cluster tool and its capabilities, and check out the National Solar Technology Roadmap for CIGS Photovoltaics. Contact Miguel Contreras for more details on these capabilities.

The Copper Indium Gallium Diselenide cluster tool, manufactured by DCA Instruments, will be operational in 2009. Techniques will include evaporation; radiofrequency, direct-current (DC), and pulsed DC sputtering; and wet-chemical-bath deposition. Collaborator tools can be attached to the central robot, enabling specific steps of CIGS solar cell deposition to be entirely customized by collaborators. All but the wet-chemical deposition chamber are maintained at ultra-high vacuum (<5x10-10 torr), minimizing contamination defects.

Applications include the following:

  • Minimizing the use of molybdenum
  • Increasing the deposition rate of high-performance processes
  • Incorporating absorber and buffer materials from collaborators into device structures developed by the National Renewable Energy Laboratory
  • Developing novel CIGS and buffer-layer deposition processes
  • Improving transparent conducting oxide materials and junctions
  • Understanding CIGS growth kinetics and chemistry
  • Improving predictive models by studying materials actually used in devices.

Basic Cluster Tool Capabilities


Sample Handling

  1. Central robot
  2. Load lock—10-platen cassette and optional port for transfer pod

Material Deposition/Device Fabrication

  1. Ultra-high-vacuum (UHV) evaporation and deposition of CIGS and other chalcogenide compounds
  2. RF sputtering (three targets) of transparent conducting oxides (TCOs) such as i-ZnO, n-ZnO, ITO, and others
  3. Radiofrequency (RF) sputtering (three targets) of CdS and other "window" materials such as ZnS and InS
  4. Direct-current (DC) sputtering of back contacts such as Mo, Cr, and Na precursors and other back-contact metals

Processing

  1. Two expansion ports—for industry support and/or for a wet station for CdS, a transfer pod, or a bridge to a second robotic unit

Measurements and Characterization

  1. Auger electron spectroscopy (AES) analytical tool—mobile unit

The figure shows where chambers—numbered in the list above—are physically located on the eight ports around the central chamber. A robotic arm moves samples from one chamber to another within the cluster tool.

Schematic overhead drawing of the Copper Indium Gallium Diselenide cluster tool. The large circular central transfer chamber is surrounded by eight ports, six of which show chambers where deposition and processing can occur. Each chamber is labeled with its function, and these labels are included in the list above on the Web page. A four-color bar below the diagram is a key to the class of capabilities of individual tools. Yellow shows sample handling; green shows material deposition or device fabrication; blue shows processing; and purple shows measurements and characterization.

Schematic of Copper Indium Gallium Diselenide cluster tool indicating the functions of its eight ports. The color bar is a key to the basic class of each capability.

Other Support Capabilities

The CIGS cluster tool contains many capabilities for CIGS research. But additional processing and integrated and stand-alone measurements and characterization capabilities are available elsewhere in the Process Development and Integration Laboratory. Samples from the CIGS cluster tool can be transported to these other tools using the mobile transfer pod, which can keep samples under vacuum conditions.