Minority Carrier Transport in Heavily Doped Silicon: Fundamental Equations

From fundamental principles, the equations that govern minority carrier transport and recombination in a heavily doped semiconductor are derived. The equations are based on three physically meaningful doping-dependent material parameters: minority carrier lifetime, mobility, and equilibrium concentration. To completely describe the problem, there is no need to use nonphysical entities like “effective doping level” or “apparent bandgap narrowing”, as has become common in the silicon device literature. Under steady state, only two parameters, which are combinations of the three fundamental ones, are relevant to minority carrier transport and recombination. These findings have important implications for parameter measurements and for the modelling of heavily doped regions in devices.