Electron and hole conduction in amorphous CVD siliconnitride layers

In amorphous CVD siliconnitride, two carrier transport with dominant hole conduction was observed in all cases. No significant differences in behaviour were found for the different gate materials used. It was also proven that the deep hole trap can act as a recombination center. The smaller conduction in LPCVD Si3N4 due to a not so shallow hole trap is responsible for the observed symmetrical behaviour of Vfb versus gate voltage for both polarities, clearly illustrating the need for LPCVD Si3N4 as an insulating layer in N-channel MNOS processes.