EBIC measurements of small diffusion length in semiconductor structures

The problems arising under submicron diffusion-length measurements by EBIC are discussed. As an example, the results of diffusion-length measurements in GaN are presented. It is shown that fitting the collection efficiency dependence on beam energy is the most reliable method for this purpose. The depth-dose dependence for GaN is calculated by the Monte-Carlo method and its analytical approximation is presented. This expression was verified experimentally by simultaneous fitting of the collected current dependence on beam energy for a few applied bias values.