Copper Indium Gallium Diselenide Cluster Tool
The Copper Indium Gallium Diselenide (CIGS) cluster tool offers powerful capabilities with integrated chambers for depositing, processing, measuring, and characterizing photovoltaic materials and devices.
The tool, manufactured by DCA Instruments, 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. Contact Miguel Contreras for more details on these capabilities.
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 NREL
- 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
- Central robot
- Load lock—10-platen cassette and optional port for transfer pod
Material Deposition/Device Fabrication
- Ultra-high-vacuum (UHV) evaporation and deposition of CIGS and other chalcogenide compounds
- RF sputtering (three targets) of transparent conducting oxides (TCOs) such as i-ZnO, n-ZnO, ITO, and others
- Radiofrequency (RF) sputtering (three targets) of CdS and other "window" materials such as ZnS and InS
- Direct-current (DC) sputtering of back contacts such as Mo, Cr, and Na precursors and other back-contact metals
- 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
- 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.
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 surrounding laboratory space. Samples from the CIGS cluster tool can be transported to these other tools using a mobile transfer pod, which can keep samples under vacuum conditions.