Method for simultaneous measurement of diffusivity lifetime, and diffusion length, with application to heavily doped silicon

A novel experimental method is presented and demonstrated that allows simultaneous determination of minority-carrier diffusivity, lifetime, and diffusion length in semiconductors. This method is based on the lateral collection of photogenerated carriers by a semi-infinite junction. The semi-infinite nature of the problem makes possible the use of closed-form expressions that greatly simplify the analysis of the experimental results. The main advantages of this method are its analytical simplicity and the self-consistency test provided by the simultaneous measurement of all three transport parameters. The effects of the lifetime and the diffusion coefficient are separated by varying the distance between the illumination edge and the collecting junction. Results of measurements for heavily doped n/sup +/ silicon with doping density of 2.4*10/sup 19/ cm/sup -3/ are demonstrated.<
>