2-PHASE STRUCTURE OF PLASMA-POLYMERIZED THIOPHENE-PASSIVATED GAAS SCHOTTKY-LIKE METAL-INSULATOR-SEMICONDUCTOR DIODES

Recently GaAs metal-semiconductor Schottky and plasma-polymerized thiophene-passivated metal-insulator-semiconductor (MIS) diodes were studied. The capacitance-voltage (C-V) results were evaluated by a simple mechanical application of the Schottky capacitance theory to the MIS devices. In this communication it is shown that there is a large discrepancy between the experimental C-V characteristics obtained for the MIS diodes and the theoretical ones following from the depletion layer capacitance theory. The only reasonable explanation of this discrepancy is a two-phase structure of the MIS devices, where one phase has a low- and the other has a high-voltage intercept of the C-2-V plot.