TESTING THE SUCCESS OF ANALYTICAL IMAGE CORRECTION ROUTINES - SURFACEIMAGES

Multispectral techniques in Auger microscopy involve the acquisition o f data as several spatially registered images or signals from the Auge r, specimen absorption current, characteristic x-ray, backscattered an d secondary electron signals. Each signal contains information from di fferent interactions and volumes within the sample. Various combinatio ns of these signals can be used along with simple physical models to r emove those contrast variations in Auger images that are not due to co mpositional variations of the sample within the Auger escape depth. Su ch contrast may, for example, be due to beam current fluctuations duri ng data acquisition, substrate backscattering or topographical effects . To measure the success of these corrections, two tests have been dev ised: the calculation of the number of resolvable levels in the Auger image before and after correction; and the measurement of the modulus of correlation \C(AR)\ between the corrected Auger image and the corre ction factor image. The tests may be used to evaluate any new image co rrection method. They have been applied to simulated and experimental data for a sample with varying subsurface composition. The results sho w that both tests are useful for evaluating the accuracy of a correcti on, and that measurement of \C(AR)\ is the more sensitive test.