Tt. Mnatsakanov et al., CHOOSING PROPER APPROXIMATION FOR SEMICONDUCTOR-DEVICE ANALYTICAL MODELING AT LOW-TEMPERATURE, Journal de physique. IV, 8(P3), 1998, pp. 71-74
The influence of nonlinear physical phenomena (namely electron-hole sc
attering, Auger recombination, reduction of the emitter junction effic
iency) on the practicality of diffusive approximation in semiconductor
multilayer device modeling is investigated. It is shown that there ex
ists a certain sequence of proper ap proximations as the current densi
ty increases. An important point is that this sequence of approximatio
ns depends on the electrophysical parameters of the structure, namely
on the ratio W/L (where W is the width of a lightly doped base layer o
f the structure, L is the ambipolar diffusion length of charge carrier
s in the base layer), the charge carrier lifetime tau and the saturati
on currents j(sn) and j(sp) of highly doped p(+) and n(+) layers. It i
s shown that at low temperature the dependence of saturation currents
on electron-hole scattering becomes of importance. Owing to this the e
lectron-hole scattering influences the validity of diffusive approxima
tion as distinct from the case of high temperature