High-speed 2D materials inspection using a microscopic dynamic spectroscopic imaging ellipsometer

Abstract

We describe a high-speed two-dimensional (2D) materials inspection method by using a microscopic dynamic spectroscopic imaging ellipsometer. This system employs a high-numerical-aperture (NA) objective telecentric lens module. Unlike conventional spectroscopic imaging ellipsometers, which require relatively long acquisition times due to rotating polarization elements, our proposed system uses a monolithic polarizing interferometric module. This allows it to extract a spatio-spectral ellipsometric phase map Δ(λ,x) of 2D materials like graphene. It achieves a spatial resolution of a few microns at a speed of a few tens of milliseconds. In this study, we demonstrate that the proposed microscopic dynamic spectroscopic imaging ellipsometer can provide spectroscopic ellipsometric phase data Δ(λ) with 165 spectral bands in the visible range. It inspects a monolayer graphene flake area of 2.5mm∗1.65mm in just 1 min, which is the fastest 2D materials inspection capability ever reported, to our knowledge.