3D Effects on Minority Carrier Recombination in Homogeneous Silicon Wafers

Calculation of three-dimensional recombination effects in homogeneous silicon wafers is performed. The current continuity equation for minority carriers with surface recombination boundary conditions is solved in cylindrical coordinates. The two most important three-dimensional recombination effects are discussed. Lateral diffusion of minority carriers gives rise to a characteristic decay inversely proportional to time. Shell surface recombination should be taken into account when measuring within the minority carrier diffusion length from the wafer edge. The discrepancy between the one-dimensional and the three-dimensional models is discussed.