The design, development and testing of the hyperbolic field analyzer

An electron energy analyzer suitable for Auger and photoelectron spectroscopy and microscopy has been designed and constructed with the objective of acquiring the entire spectrum (50 to 2500 eV) emitted from a solid. The dispersion is provided by an approximation to a hyperbolic potential distribution and the spectrum is detected on a plane at one bound of the analysing structure. In the first version of the hyperbolic field analyzer (HFA) the spectrum is amplified by a micro-channel plate and detected with a phosphor-coated glass screen inside the vacuum and a 512 channel CCD camera outside. In the second, the micro-channel plate is retained and the detector is an, in vacuo, integrated, 1024 channel photodiode array equipped with fibre optics and a phosphor coating. The properties of various HFA based structures have been simulated and optimised using both in-house software and the SIMION (6.0) package. Particular attention has been given to the dispersion and energy resolution as functions of the kinetic energy of electrons focussed onto the detection plane. The first version of the analyzer has been used to demonstrate spectra from Cu, Ag, and a variety of surface contaminants and particulates. Further, the time dependent desorption of Cl from InP under electron bombardment has been investigated with this version of the HFA. The energy resolution of the analyzer scales as E1/2 and is ∼4 eV at 900 eV - this being limited by the pixel size of the CCD camera. The second version of the analyzer has an improved approximation to a hyperbolic field and 1024 channels of detection. The energy resolution scales in the same manner as the version but is ∼4.4 eV at 2000 eV. The results of the simulations are compared with the characteristics measured for this version and chemical mapping along a contaminated gold surface was demonstrated. (author)