  The classical Shockley boundary conditions are used for the determination of
the minority carrier concentrations at the edges of the space-charge region of
semiconductor p-n junctions. They are usually employed for the calculation of
the p-n junction current/ voltage characteristic. This work demonstrates that
they are valid only at low injection current levels. New analytical expressions
for these boundary conditions are obtained for medium and high injection
levels. These expressions are verified by calculating the current/ voltage
characteristics of p-n junctions operated at high current levels.
