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Internet-based Performance Centred Instruction
Advanced lithography tutorial

Modules

1. Electron beam lithography
2. X-ray lithography
3. Ion beam lithography
4. Nanolithography

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  • Scanned probe lithography
    • uses the AFM equipment
    • the tip is placed in the vicinity of a surface
    • a high electric field is applied between the tip of the probe and the surface
    • HO- ions diffuse due to the electric field into the material and oxide is grown where the is placed
    • the oxide grown is localised to a very small spot -  high resolutions can be obtained
    • the distance between the tip and surface is controlled as in AFM by system comprising of :
      • cantilever - the arm of the probe
      • optical lever deflection sensor, which senses the position of the tip by measuring the reflection of a laser beam on top of the probe
      • scanner to modify the tip position mechanically
      • the current measured between the probe and the surface (for conductive surfaces) gives information on how much force should be applied in order to maintain the distance constant
    • carbon nanotubes can be used as tips for SPL
      • they are conjugated carbon molecules having delocalised p-electrons
      • can have diameter in the order of nanometers - very small
      • they can add material or etch it from a surface - nanotubes are very hard from the mechanical point of view
  • Dip-pen lithography
    • is similar to SPL, done also with an AFM tip
    • the tip has the property that material can be inserted in it (like ink in a pen) and when it is brought close to a surface, the material from the tip is "written" on the surface
    • 15 nm structures can be made

                              

1. Electron beam lithography
2. X-ray lithography
3. Ion beam lithography
4. Nanolithography

pages: [1] 2 3 | next

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