On the theory of spatial resolution enhancement in the SEM functioning in the beta-conductive mode

We consider a problem aimed at increasing the resolution of the scanning electron microscope in the beta-conductivity regime. It is shown that the full analysis of the problem requires investigation of the following aspects of the signal formation in the scanning electron microscope operating in the beta-conductivity regime. Firstly, one needs to calculate the region of scattering of the probe electrons in the volume of the semiconductor in the presence of tangential electric fields. Secondly, one has to study the dynamics of the volume of minority carriers generated by the electron probe as a result of diffusion under the action of electric fields in the object, in the presence of surface recombination. By using a number of assumptions, we analyse the equations for the diffusion of carriers, calculate the concentration for various values of the E field'and surface recombination rate during the pulse of electron current. It is shown that the volume taken up by the electron-hole pairs (the signal volume) depends strongly on the values of the E field and the surface recombination rate. We note that, by using the stroboscopic regime in the scanning electron microscope, one can increase the resolution in the case of beta-conductivity by a factor of 2 - 3.