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Silicon Cluster Tool

The Silicon cluster tool is a 10-port cluster tool designed by the National Renewable Energy Laboratory (NREL) and manufactured by MVSystems.

Photo of the Solar Energy Research Facility

It handles standard 157-mm × 157-mm samples introduced into the central 10-6 torr vacuum chamber via a load lock. From there, a robotic arm moves samples from one chamber to another within the cluster tool. Contact Pauls Stradins for more details on its capabilities.
Applications include the following:

  • Researching techniques and parameters for record-efficiency solar cell fabrication
  • Monitoring material growth in situ
  • Carrying out high-throughput experiments on the impact of sample thickness and depositional temperature
  • Exploring potential industry practices for fabricating silicon solar cells
  • Studying amorphous silicon (a-Si)-based films (a-Si:H, a-SiGe:H, a-SiNx:H, and a-SiCx:H) and nanocrystalline silicon (nc-Si) films (nc-Si:H and nc-SiGe:H), transparent conducting oxides (TCOs), thin-film transistors, and thin-film diodes
  • Researching single junctions, tandems, crystalline silicon (c-Si) heterojunctions, surface passivation, and hydrogenation

Basic Cluster Tool Capabilities

Sample Handling

  • Sample and mask loader
  • Transport pod for inter-tool sample transport
  • Vacuum robot for intra-tool sample transport

Material Deposition/Device Fabrication

  • Very-high-frequency plasma-enhanced chemical vapor deposition (VHF PECVD) for microcrystalline silicon (µc-Si:H)
  • Combinatorial plasma-enhanced chemical vapor deposition (Combi-PECVD) for p-type a-Si:H
  • Plasma-enhanced chemical vapor deposition (PECVD) for n-type a-Si:H
  • Combinatorial plasma-enhanced chemical vapor deposition (Combi-PECVD) for intrinsic a-Si:H
  • Plasma-enhanced chemical vapor deposition (PECVD) for SiNx antireflective coating
  • Combinatorial hot-wire chemical vapor deposition (Combi-HWCVD) for intrinsic a-Si:H
  • Sputtering for metal contacts and TCOs

Processing

  • Plasma etching at ultra-high (10-8 torr) vacuum

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

This schematic of the Silicon cluster tool indicates the tools connected to the ten ports. The color bar is a key to the basic class of each capability.

Other Support Capabilities

The Silicon cluster tool contains many capabilities for silicon research. But additional capabilities for processing, integrated measurements and characterization, and stand-alone measurements and characterization are available elsewhere in the same laboratory space. Samples from the Silicon cluster tool can be transported to the other tools using a mobile transport pod, which can keep samples under vacuum conditions.