title: Near-field nano-ellipsometer for ultrathin film characterization.
abstract: We describe a near-field ellipsometer for accurate characterization of ultrathin dielectric films. Optical tunnelling mimics the absorption in metallic films, enabling accurate measurement of the refractive index of ultrathin dielectric film. A regression model shows that a refractive index resolution of 0.001 for films as thin as 1 nm is possible. A solid-immersion nano-ellipsometer that incorporates this near-field ellipsometric technique with a solid-immersion lens is constructed to demonstrate the viability of this technique. Such a nano-ellipsometer can accurately characterize thin films ranging in thickness from subnanometre to micrometres with potential transverse resolution of the order of 100 nm.
authors.affiliation: Department of Electrical and Computer Engineering, University of Minnesota, 4-174 EE/CSci Building, 200 Union Street SE, Minneapolis, MN 55455, USA. qiwen.zhan@notes.udayton.edu
authors.forename: Q
authors.initials: Q
authors.lastname: Zhan
authors.forename: J R
authors.initials: JR
authors.lastname: Leger