Analysis of Electron Beam Induced Current Considering Sample Dimensions–Measurement of Diffusion Length and Surface Recombination Velocity–

Abstract

The electron beam induced current (EBIC) in a sample was analyzed, taking the sample dimensions into account. The minority carrier distribution is greatly affected by the length w between a potential barrier and an ohmic contact, if w is equal to or smaller than one diffusion length. The EBIC was calculated by a simple method using an image source-and-sink distribution. For L<w, the logarithm of EBIC J decreases linearly in the middle range of the scanning distance x. The value of L estimated from the slope of the log J vs. x curve is much shorter than the real diffusion length. L must be determined by considering the influences of ohmic contact and surface recombination. If L is greater than w, the slope of the curve in the linear region does not change even if L varies. Therefore, L cannot be determined definitely from the slope of the curve. Experimental results in Si Schottky diodes showed good agreement with the theory.