Three-step phase-shifting imaging ellipsometry to measure nanofilm thickness profiles

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Three-step phase-shifting imaging ellipsometry is proposed for the dynamic measurement of a nanofilm's thickness profile in two dimensions. The designed apparatus consists of an ellipsometric optical configuration and an image-processing unit to perform phase-shifting imaging ellipsometry measurements, a key technique used to achieve dynamic and two-dimensional measurements. The uncertainties of the ellipsometric parameters ψ and Δ were evaluated based on the developed optical system and the proposed three-step phase-shifting technique. The thickness profile of a SiO2 nanofilm on a silicon substrate was measured to calibrate the proposed apparatus; results were comparable to those obtained by a commercial spectroscopic ellipsometer. The measured thickness profiles are almost flat over the area of 1.10 mm × 2.21 mm with the spatial resolutions of 1.58 and 4.62 μm in the horizontal and vertical directions, respectively. The differences of average thickness between the proposed apparatus and a commercial spectroscopic ellipsometer were less than 3 nm. Furthermore, measurement precision was validated by obtaining a standard deviation of less than 2.5 nm.

Original languageEnglish
Pages (from-to)145-150
Number of pages6
JournalOptics and Lasers in Engineering
Publication statusPublished - 2019 Jan


  • Ellipsometry
  • Nanofilm
  • Phase-shifting technique
  • Thickness measurement

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Mechanical Engineering
  • Electrical and Electronic Engineering


Dive into the research topics of 'Three-step phase-shifting imaging ellipsometry to measure nanofilm thickness profiles'. Together they form a unique fingerprint.

Cite this