Variation in the effective richardson constant of metal-GaAs and Metal-InP contacts due to the effect of processing parameters

The value of experimental Richardson constant (A*) is found to be a function of metal film thickness, type of the metal, method of deposition, and condition of semiconductor prior to metal deposition. In the case of Al and W on GaAs, the value of A* is found higher than the theoretical value. However, as the film thickness increases, the value of A* decreases. The larger value of A* is related to electrically active defects at the interface produced during sputtering. Filament evaporation results in smaller values for A*. In the case of WSi0.6 the presence of Si affects the value of A*. For InP, the value of A* is found smaller than the theoretical value. For both GaAs and InP, the value of A* increases when the semiconductor is annealed prior to metal deposition. This increase is significant in the case of InP.