AVS 47th International Symposium
    Material Characterization Tuesday Sessions
       Session MC-TuP

Paper MC-TuP16
Surface Potential Measurement with High Spatial Resolution using a Scanning Auger Electron Microscope

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: C. Nielsen, JEOL USA Inc.
Authors: Y. Sakai, JEOL Ltd., Japan
M. Kudo, JEOL Ltd., Japan
C. Nielsen, JEOL USA Inc.
Correspondent: Click to Email
The microscopic surface potential distributions were measured from the onset energies of secondary electron spectra using a scanning Auger electron microscope. An equipment used in this experiment was a scanning Auger electron microscope (JEOL Model JAMP-7830F) attached with a hemispherical electron energy analyzer with an input focusing lens system and a secondary electron detector to take SEM images. The electron gun is a Schottky field emission type and electrons emitted from a cathode tip are focused onto the specimen surface. The hemispherical electron energy analyzer with a high detection efficiency in the region lower than several ten eV was used at an ultra-high vacuum pressure. Such a technology makes possible to measure the work function change caused by different crystal orientations, the surface potential profile depending on micro-electronic structures of semiconductor devices, etc. The typical applications of the work function measurement are presented in this paper. The four grains of poly-crystal Ni (99.9% purity) with different crystal orientation were prepared for testing a spatial resolution of work function mapping. The initial rises of secondary electron emission for the four grains of Ni are observed by the primary electron beam at 10 keV and 1.3 n A., and the onset energies are 5.55, 5.60, 5.65, and 5.50eV, respectively. If we put the work function of the analyzer equal to 5.60 eV, the work functions of Ni are 4..95, 5.04, 5.22 and 5.35 eV, respectively. The mapping of work function distribution was carried out by measuring intensities of secondary electron emission at the fixed point of. 5.70eV. The observed work function images show a spatial resolution of several tens nm estimated from the image contrast. The measurement of work function and imaging of the surface potential at a spatial resolutions of several tens nm and a sensitivity of 0.05V have been established by using a scanning Auger electron microscope of ultra-high vacuum.