Phosphor coated waveguide for efficient collection of electron-generated photons

Abstract

A phosphor coated waveguide for efficient collection and detection of back-scattered electrons in an electron beam apparatus such as a scanning electron microscope is disclosed. The waveguide for directing photons to an optical detector generally comprises a first waveguide portion having opposing first and second faces defining a beveled hole therebetween to allow an electron beam to pass therethrough, the beveled hole decreasing in cross-sectional size from the first to the second face. A phosphor coating on the second face around the beveled hole converts the back-scattered electrons to photons. The first waveguide portion may include angled faces at an end further from the optical detector. A surface defined by the beveled hole and/or the angled faces may have a reflective coating. The waveguide may also include a second waveguide portion that adjoins and flares out relative to the first waveguide portion to further increase waveguide efficiency.

Dependencies are inferred from the claim text.