EDGE EFFECTS AND IMAGE-CONTRAST IN SCANNING AUGER MICROSCOPY - A THEORY EXPERIMENT COMPARISON

We report on both theoretical (Al and W) and experimental (Al and Au) results for sharply edged overlayers of Al, W and Au on a Si substrate, where the heights of the overlayers (0. 6 mu m to 1. 4 mu m) were sufficiently large that the effects of scattering from the overlayer edges are much larger than in the case reported by Tuppen and Davies. Both the polar ( PHI ) and azimuthal ( theta ) angles of the incident electron beam have been varied and were found, together with the height of the edge, to combine in producing several effects that should be taken into account in the interpretation of SAM images. Techniques currently employed to reduce such effects will be demonstrated and assessed while suggestions for possible reduction of the magnitude of these effects will be given.