The influence of the combined effects of high injection level and heavy doping on the characteristics of silicon p(+)-n-n(+) solar cells is examined. The total amount of nonlinear physical phenomena (Auger recombination, electron-hole scattering. band-gap narrowing, charge carrier lifetime and transport coefficient reduction in the heavily doped layers of the structure) is taken into account. It has been established that a combined process which includes the generated charge carrier overflowing from n-base layer to highly doped n(+)-type and p(+)-type layers of the structure and their subsequent recombination in these highly doped layers, proves to be of great importance in silicon solar cells. The influence of electron-hole scattering on charge carrier transport in the highly doped nf-type and p(+)-type layers has been investigated for the first time. It has been found that minority carrier complete drag phenomenon results in a significant decrease of n(+)-type and p(+)-type layer saturation currents.