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How to Make a Circular Superconductor Track

Electrical resistance is due to electrons scattering off one another and off the sides of the wire. Certain materials exhibit no electrical resistance below a critical transition temperature, and these materials are known as superconductors. Any material such as a superconductor can be patterned into a certain shape, such as a circular track, using a process known as photo-lithography. This process involves the shining of ultraviolet light through a specially designed mask -- a plate that acts like a stencil -- in order to generate a pattern.

Things You'll Need

Spin coater
S1813 photo-resist
S1813 developer
Mask aligner
Mask with circular track
Evaporation chamber
Niobium pellets
Hot plate
Si substrate

Instructions

- 1
  Place the silicon substrate on the spin-coater chuck. Select a spin speed of 3000 RPM, and a spin time of 2 minutes. Place a few drops of S1813 onto the substrate and start the spinning.
- 2
  Turn on the hot plate and set it to 110 degrees Celsius (230 degrees Fahrenheit). Wait until the hot plate has reached the set-point temperature. Place the sample on the hot plate for 2 minutes. Remove the sample and leave it to cool.
- 3
  Place the sample in the mask aligner, and place the mask with the circular track into the mask aligner above the sample. Expose the sample to ultraviolet light for 2 seconds.
- 4
  Place the sample into the S1813 developer for 30 seconds. The developer removes the exposed parts of the sample, forming a circular track that superconducting material can be deposited into.
- 5
  Place the sample into the evaporator, and place a few pellets of Niobium into the evaporation crucible. Evaporate 100 nanometers of Niobium. Remove the sample from the evaporation chamber. Place the sample into acetone. Acetone removes all parts of the photo-resist leaving the superconducting circular track. The sample is complete. Niobium is superconducting below 9.3 Kelvin.

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