ELECTROSTATIC LENS HAVING A DIELECTRIC SEMICONDUCTING MEMBRANE

摘要

Electrostatic lenses for focusing a beam of charged particles, and in particular an electron beam, are used especially in the electron guns of electron microscopes or electron-beam lithography apparatuses. The present disclosure improves the possibilities for focusing the particle beam, in particular an electron beam emitted by a cathode. The lens comprises at least one conducting electrode having at least one through-opening for the passage of an electron beam. Different electric fields are set up upstream and downstream of the opening. The passage opening is at least partially closed by a planar or curved thin membrane of semi-conducting material that is transparent to electrons and has a high dielectric permittivity. Structuring the membrane (holes or thickened portions of electrodes deposited on the membrane) makes it possible to correct lens aberration defects.

主权项

1. An electrostatic lens provided with at least one conductive electrode pierced with at least one aperture for passing an electron beam, wherein the passing aperture is closed at least partially by a thin membrane (M) of a non-degenerate semiconductor that is transparent to the electrons of the beam and of relative dielectric permittivity higher than 10.