The multilayer silicon nitride films as a media for charge storage in MNOS structures

Abstract

Charge storage in multilayer silicon nitride films of MNOS structures is investigated and compared with homogeneous films. Multilayer silicon nitride films were synthesized using nonmonotonical step changing of the NH/sub 3/ to SiCl/sub 4/ ratio during deposition. The energy bandgap of Si/sub 3/N/sub 4/ and energy barrier heights for electrons and holes change appreciably, depending on the reactive component ratio. In forming the multilayer silicon nitride films we created a graded bandgap insulator with energy wells and barriers. This allows the current transport and distribution of stored charge in the insulator of MNOS structures.