Localized density of states in hydrogenated amorphous silicon/silicon nitride interfaces studied by transient voltage spectroscopy

The localized electronic density of states gL(E) at the hydrogenated amorphous silicon/silicon nitride (a-Si:H/Si3N4) interfaces was examined by transient voltage spectroscopy. The gL(E) at the a-Si:H/Si3N4 interface was observed to have a broad peak and a deep minimum, respectively, around 0.9 and 0.47 eV below the conduction-band edge. The positive fixed charge at the interface makes the flatband voltage of the a-Si:H/Si3N4 system negative. Therefore, there is a finite band bending at the interface even at the gate bias of 0 V.