The novel surface science instrument: Double reflection electron emission microscope

A universal UHV instrument, the double reflection electron emission microsc ope (DREEM), for surface imaging, diffraction, and local (1 mu m resolution ) measurements is presented. DREEM consists of three fully electrostatic le ns systems: electron gun column, immersion objective lens, and imaging colu mn. The novel illumination system incorporates an electron microreflector i n the back focal plane of the objective, where the perpendicular optical ax es of the electron gun and imaging column cross. The electron microreflecto r consists of the tip of a (001)-oriented single-crystalline W wire with a face of area 200 mu m(2). The primary electrons of energy from 1 to 6 keV e lastically reflect from the W tip surface and are decelerated between the o bjective and grounded sample to the desired impact energy from 0 eV to 5 ke V. Numerous contrast mechanisms are expected for image formation with DREEM including topographic, magnetic, chemical (Auger, core level), phase shift , and work function. The instrument is capable of operating in low energy e lectron diffraction, mirror electron microscopy, low energy electron emissi on microscope, and photoelectron emission microscope modes. The first resul ts obtained with the DREEM are presented. (C) 1999 American Institute of Ph ysics. [S0034-6748(99)03408-5].