Thin oxide interface layers in a-Si: H MIS structures

Pd-metal/insulator/semiconductor based on hydrogenated amorphous silicon were produced by plasma enhanced chemical vapour deposition with two different oxidised surfaces: thermal in ambient air and chemical with hydrogen peroxide. The diode characteristics have been investigated using dark and light current as f(v) measurements in the temperature range from 300 K to 380 K, from which it was possible to infer the electron barrier height. The data obtained show that the incorporation of a thin insulator layer between the semiconductor and the metal improves the performances of the devices by preventing the formation of suicides at the interface. Apart from that we also show that the MIS structures with the thermal oxide presents 'better' performances than the ones with the chemical oxide due to the type of interface states and of the oxide charges associated with the interface between the insulator and the semiconductor.