Silicon nitride (Si3N4) is an amorphous semiconductor material used in floating gates of MONOS flashes and in charge-trap flashes (CTF).
Silicon nitride has the advantage over other semiconductors that it is non-conductive and no charge carriers will leak out if there are leaks in the silicon nitride layer.
Silicon nitride belongs to the high-k dielectrics and has a permittivity of 7. The band gap is 5.1 electron volts (eV). It is also used for the passivation of solar cells for the back surface field, the Black Surface Field (BSF), in order to increase the efficiency of solar cells.