Fabrication of Photonic Crystal Structures by Electron Beam Lithography

A variety of photonic crystal structures have been patterned using an electron beam lithography instrument developed by modifying a scanning electron microscope. The cumulative dose lithography technique developed for use with this instrument has enabled dense structures such as photonic crystals to be efficiently fabricated. This technique overcomes the need for large pattern data files and minimises the number of shapes to expose in order to produce the final structures. This has the advantages of reducing the time spent blanking and unblanking the beam and minimizing the effect of artifacts due to beam blanking on a large number of shapes. The lithography pattern data files are also reduced in size and the characteristic benefits of electron beam lithography are retained. These include the wide range of line widths available and the ability to rapidly vary the topology of the fabricated structures by changing only the pattern data files since no exposing mask is required.