Schottky-barrier behavior of metals on n- and p-type (formula presented)

The Schottky-barrier height of a number of metals (Ti, Ni, Cu, and Au) on n- and p-type Si-terminated (formula presented) has been measured in the temperature range 150–500 K. It is found that the barrier height to n-type (formula presented) does not exhibit a temperature dependence, while for p-type (formula presented) the change in the barrier height with temperature follows very closely the change in the indirect energy gap in (formula presented) These results are inconsistent with models of Schottky-barrier formation based on the concept of a charge neutrality level. Furthermore, the present results cannot be reconciled with a defect pinning mechanism, contrary to the conclusions of earlier studies on III-V compound semiconductors. We suggest that chemical bonding at the metal-semiconductor interface plays an important role in determining the Schottky-barrier height. © 2003 The American Physical Society.