Schottky barriers on InSb

Abstract

Schottky barriers formed on air-cleaved InSb are found to be more reproducible and have less leakage than diodes fabricated by chemical processing. Etched surfaces yield diodes with large leakage currents and high series resistances whose values are correlated, i. e. , high series re-sistances have less leakage and vice versa. With air-cleaved surfaces the lowest leakage is observed when the surfaces adjoining the contact are covered with SiO2. From C-2 versus V data, barrier heights of 50 mV and 175 mV at 77K are measured for Au contacts to n- and p-type InSb, respectively. The current-voltage characteristics of Au contacts are consistent with these barriers, but the low-temperature field-emission behavior appears to be dom-inated by tunneling via traps. For Pb contacts, deep-level traps are in evidence that can lead to erroneous in-terpretations of C-2 versus V voltage intercepts. The I-V data for Pb contacts suggest VBn ≈0 and VBp ≈Eg/q. Diodes fabricated on vacuum-cleaved surfaces have large leakage currents which result from the etching procedures introduced to isolate individual diodes.