Temperature-dependent low electric field charging of Si nanocrystals embedded within oxide-nitride-oxide dielectric stacks

摘要

In this work we examine the current peaks and the negative differential resistance that appear in the low electric field regime of oxide-nitride-oxide structures with a two-dimensional band of silicon nanocrystals embedded in a nitride layer. The silicon nanocrystals were synthesized by low energy ion implantation (1 keV, 1.5 × 10~(16)Si~+ cm~(-2)) and subsequent thermal annealing (950 ℃, 30 min). Electrical examination was performed at temperatures from 20 to 100 ℃ using constant voltage ramp-rate current measurements. This approach enables us to determine the origin of the observed current peaks as well as to extract the trapping location of the injected carriers within the dielectric stack. The results confirm that the carriers are trapped within the Si nanocrystal band, verifying that this region corresponds to energy minima of the dielectric stack.