Silicon substrate effects on the current-voltage characteristics of advanced p-n junction diodes

An in-depth analysis of the forward and reverse current-voltage characteris tics allows determination of the different geometrical (area, perimeter and corner) and physical (diffusion and generation) current components. This i s a powerful technique to assess the silicon substrate quality. In this pap er it is shown that the diffusion current of a good quality silicon p-n jun ction is significantly lower for an epitaxial (Epi) wafer compared to a Czo chralski (Cz) wafer. This can be explained by a correction factor, F, which depends on the parameters of the highly doped substrate. The impact of the substrate is less pronounced when the leakage current is dominated by the peripheral component. Furthermore, for low reverse bias, current transients occur for large area diodes in Ct substrates. These are related to the pre sence of generation centres, which are absent in epitaxial wafers. (C) 2000 Elsevier Science S.A. All rights reserved.