Capabilities

Generally speaking, the Solar Fab supports cell fabrication, module creation, and reliability testing.

The lab has all the necessary processing equipment for raw silicon to serve as the input, and completed, characterized, and tested solar cells generated as the output.

  • Wet processing - Like semiconductor fabrication, solar cell processing requires intensive wet processing operations. Standard wet processing cleans such as RCA-A, RCA-B, piranha, BOE, saw damage removal, and texturing can be performed in the Solar Fab.
  • Screen printing - Owing to the need for inexpensive fabrication of solar cells, screen printing is used for patterning operations.
  • Thermal operations - Standard processes exist for paste drying and paste firing, along with the ability to grow dry thermal oxides. Additionally, both rapid thermal annealing and tube annealing in Ar, O2, N2, and H2N2 are available. Finally thermal diffusion of P capability exists.
  • Electroplating - Light induced plating of Ni, Cu, and Sn and conventional electroplating of Cu can be performed.
  • Deposition - Deposition capabilities in the Solar Fab include e-beam evaporation, both DC and RF sputtering, PECVD, and MBE.

The Solar Fab also fabricates modules, usually single-cell or 2x2 format, but a few larger modules, up to 36-cells, have also been made.

  • Module fabrication - Soldering, paste dispense, and up to full-size module lamination of solar cells is possible in the lab.
  • Laser processing - Cutting substrates and fusing materials are possible with wavelengths from 1064 - 10600 nm.

Core reliability testing such as damp heat exposure and thermal cycling is available.

  • Reliability - Dedicated damp heat and thermal cycle testing of single-cell and two-by-two module formats can be performed.

In addition to the above capabilities, various concomitant characterization techniques are also available in the Solar Fab. In turn, these characterization techniques may be classified as in-situ or post fabrication.

  • In-situ - Capabilities include reflectometry, profilometry, bright light and microscope inspections, gauge thickness, weight change, resistivity, photoluminescence/electroluminescence, and spectrophotometry.
  • Post Fabrication - Quantum efficiency, steady state and flash I-V, and lock-in thermography are examples of available characterization techniques.