Dependence of Barrier Height of Metal Semiconductor Contact (Au–GaAs) on Thickness of Semiconductor Surface Layer

In this work it is experimentally shown that the apparent potential barrier height at a metal-semiconductor interface (Au–GaAs) is related to the thickness of the semiconductor surface ``oxide films''. The barrier height was measured by capacitance-voltage and photoelectric techniques. The surface layer seems to behave approximately as described by Cowley and Sze, and can account for a variation from 0.82 to 1.08 eV in measured effective barrier height. However, for a more complete explanation of the experimental results it seems likely that additional parameters, such as charge, surface states, and band structure in the surface layer, will have to be taken into account.