Compensation of shadow effect for one-dimensional diffractive structures via an approach of microfabrication

Yongqi Fu, Ngoi Kok Ann Bryan, David Butler

Research output: Contribution to journalArticlepeer-review


A compensation method is introduced from the microfabrication perspective for the purpose of degrading the shadow effect of diffractive structures. A dead blaze area ε that is generated during the fabrication process makes a great contribution to the shadow effect. Our experiments have demonstrated that it can be reduced by tilting the work stage to a certain angle during the direct writing of the focused ion beam (FIB). The redeposition effect, round effect, and discrimination error of the FIB affect the compensation of the shadow effect and cause the dead blaze area to still exist more or less after the compensation when the stage-tilting angle is less than 50°. The compensation can be further improved with the aid of chemical gas assistant etching. In addition, two important factors relevant to the compensation, characterization errors from atomic force microscopy and optical interferometry, and limitation of depth of focus, are discussed in detail.

Original languageEnglish
Article number093116
Number of pages7
JournalReview of Scientific Instruments
Issue number9
Publication statusPublished - 30 Sep 2005


  • microfabrication
  • diffractive structures
  • shadow effect
  • focused ion beam (FIB)


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