Characterization of plasma-deposited silicon nitride films

Abstract

Structural and electrical properties of plasma-deposited silicon nitride (SiN) have been investigated. The compositional ratio of Si to N estimated by Auger analysis is found to be uniform in the direction of the film thickness. The numbers of Si-H and N-H bonds of the order of ∼1021/cm3 have been obtained by calculating the vibrational spectra. The two types of trapping states which are responsible for the Poole-Frenkel conduction are found in SiN from the current DLTS measurement. The barrier height at the SiN/Si interface determined by the internal photoemission ranges from 1.7 to 2.5 eV, being dependent on the film thickness. From these results, current transport mechanisms through SiN films are quantitatively discussed, and it is demonstrated that the carrier transport is dominated by the Fowler-Nordheim tunneling at low temperatures and by the Poole-Frenkel conduction at high temperatures.