No abstract

Physical, chemical and electrical properties of Si rich silicon nitride (SiN) film deposited by using the SiH4–NH3 system have been studied. By changing the volume ratio of NH3 to SiH4 from 100 to 1/30, samples with varying excess Si content within SiN films can be obtained. The current conduction mechanism of the SiN film can be represented by the superposition of Poole-Frenkel current, field ionization current and hopping current as reported by Sze in the Si3N4 films without Si excess. Energy levels of trapping centers responsible for Poole-Frenkel current become shallow while their densities remain nearly constant as a function of the Si content. From the dependence of the shift characteristics of C–V curves, it has been deduced that the maximum charge storage within the SiN film is controlled by current conduction through the film.