Investigation on the oxide field dependence of hole trapping and interface state generation in SiO2 layers using homogeneous nonavalanche injection of holes

Abstract

Homogeneous injection of holes into the gate oxide of metal-oxide-semiconductor (MOS) devices was obtained using p-channel MOS transistors under illumination conditions. Because gate hole currents could be measured the dependence of the hole trapping on the oxide electric field and on the energy of the holes at the injection point could be investigated. In contrast to results recently reported for electron injection no evidence for the generation of traps during hole injection was found. Only a small dependence of the capture cross section on the oxide field was observed. The study of the interface state generation during hole injection at various fields revealed that the amount of interface states directly generated by the injected holes is less than 5% of the number of trapped holes. For longer times a transformation process occurs and a correlation is found between the detrapping of holes and the generation of interface states.