Fabrication of amorphous silicon nitride thin films by radio-frequency sputtering assisted by an inductively coupled plasma

We have investigated the preparation of amorphous silicon nitride (a-Si1-xNx:H) thin films by reactive RF sputtering assisted by inductively coupled plasma (ICP) with argon (Ar), hydrogen (H-2) and nitrogen (N-2). The ICP assist system gives the high density ICP mode plasma near the substrate with relatively low plasma potential and electron temperature by applying >50 W to the ICP antenna coil. The E-04 band gap is successfully controlled from 2.2 eV to 33 eV by changing the RF power to the antenna coiL The ICP mode plasma significantly enhances the formation of Si-N bonds in a-Si1-xNx:H films, due to the effective generation of N radicals near the substrate. The ICP mode plasma also gives the high deposition rate for wide band gap a-Si1-xNx:H films. A small N2 gas ratio (<1%) is enough to produce wide band gap a-Si1-xNx:H films, therefore, a sufficient Ar gas ratio can be maintained for the Si sputtering. This method gives a simple and effective process to produce wide band gap a-Si1-xNx:H films with a relatively high deposition rate. (C) 2017 Elsevier B.V. All rights reserved.