SEPARATION AND ANALYSIS OF DIFFUSION AND GENERATION COMPONENTS OF PN JUNCTION LEAKAGE CURRENT IN VARIOUS SILICON-WAFERS

An analytical method to separate the diffusion and generation componen ts of pn junction leakage currents is developed. The voltage dependenc e between reverse current and capacitance in pn junctions is measured, and an approximately linear relationship between current density (J) and depletion width (W) is derived. In this relationship, the diffusio n component corresponds to linearly extrapolated value of J at W=0, an d the generation component corresponds to the rate at which J increase s with W as voltage is applied. This method allows both components of the leakage current to be obtained for Czochralski, epitaxial, and int rinsic gettering wafers. Separated diffusion components strongly depen d on silicon wafers mainly due to the change of minority carrier densi ty and the diffusion of minority carriers. On the other hand, the gene ration component increases with increases in the electric field applie d to the junction for all wafers. We found that this electric field ef fect on the generation component can be explained by the Poole-Frenkel mechanism.