Effective barrier heights of mixed phase contacts: Size effects

Computer simulations of mixed phase Schottky contacts have been performed to gain insight into the effects of lateral dimensions upon device behavior. As expected, lateral dimensions comparable to the Debye length of the semiconductor result in strong modification of the device characteristics that would result from independent, parallel diodes. We suggest that such effects can play a role in most experimentally obtained contacts. Current models of Schottky barrier formation typically invoke kinetics-limited chemical interactions at the metal-semiconductor interface; such effects are unlikely to be laterally uniform over macroscopic dimensions, and may well provide strong sensitivity to seemingly minor variations in preparation techniques used by different groups. We demonstrate that mixed phase contacts, with size effects, can affect ideality factors, and can also cause disagreement between C-V and I-V barrier heights.