Injection amplification effect in the metal-ferroelectric-insulator-semiconductor thin film structure

Abstract

The example of ferroelectric films of barium strontium niobate (BSN) deposited on a silicon substrate with a thin ( ca. 10 nm) silicon nitride sublayer was used to show that the specific features of the process of injected charge accumulation in metal-insulator-ferroelectric-semiconductor structures manifest themselves in the effect of amplification of the charge carrier injection from the semiconductor due to the formation of the polarization charge in the ferroelectric, as compared with the corresponding metal-insulator-semiconductor structures. It was established that the introduction of an additional layer of BSN into standard metal-nitride- oxide-semiconductor (MNOS) memory elements leads to a decrease in the writing voltage by a factor of 1.5–2.5, with a simultaneous increase in the number of write- erase cycles by 2–3 orders of magnitude, while the charge storage time remains the same as for the MNOS structures.