Influence of plasma on silicon surface during low-energy plasma deposition process: The comparative study on Si3N4/Si structures

The use of plasma-enhanced chemical vapor deposited silicon nitride (Si3N4) in the role of both passivation of semiconductor devices and electrically active layer is primarily determined by the Si3N4/Si interface quality. To enhance the control of the interface formation, we separated the deposition of the Si3N4 into two steps; At the beginning, we deposited a ‘‘shielding’’ Si3N4 layer in the remote mode, including minimal damage of the silicon surface. This layer would hamper the deterioration of the insulator/semiconductor interface properties by the energetic species bombardment during the following ‘‘quick’’ deposition of a thick bulk dielectric layer in the direct mode. On the base of small-signal charge deep-level transient spectroscopy of metal-nitride-silicon capacitors, we found the inserted remotely deposited Si3N4 layer with a thickness of about only 2–3 nm is able to effectively avert the energetic radiation-induced damage of the silicon surface.