ON THE CONTRIBUTION OF RECOMBINATION CURRENTS IN SCHOTTKY-BARRIER DIODES

It is demonstrated that for Schottky diodes with barrier heights of the order of 0.7 eV the bulk depletion region recombination is unlikely to be responsible for significant deviations from unity of the diode ideality factor, m; that is in the range 1.02 < m < 1.10. The reason lies in a saturation effect which arises because the point of maximum recombination, where electron and hole concentrations are equal (n = p), is close to the metal/semiconductor interface. For increasing (but low) bias, the condition n >> p prevails, causing the recombination process to become increasingly limited by the hole concentration, which changes insignificantly with increasing forward bias. The recombination current thus reaches a maximum at low bias, and then saturates. Alternative parasitic mechanisms and the implications for technologically important diodes are discussed.