Intrinsic Electron Trapping in Amorphous Silicon Nitride (a-Si3N4:H)

Abstract

Silicon nitrides are widely used in electronics, most notably as the charge trapping layer of memory devices. While dangling bonds and vacancies have been identified as possible trapping centers to store charges in these materials, here we argue that intrinsic defects also contribute to the trapping and storing of electrons in amorphous Si 3 N 4 :H. This is because our ab initio investigations show that prolonged Si-N bonds can act as trapping sites for electrons in the amorphous network. The trapping sites are statistically analyzed in terms of their structural properties and bond order. By calculating relaxation energies, charge transition levels and energy barriers for charge capture and emission at these sites, we demonstrate that prolonged Si-N bonds can trap and store electrons in Si/Si 3 N 4 systems, potentially contributing to the memory effect in charge trap flash devices.