A novel method for the deposition of Si-SiO_2 superlatives

摘要

A novel procedure is proposed for the deposition of Si/SiO_2 multilayers by magnetron sputtering of an SiO_2 target under a hydrogen-rich plasma. The effect of increasing hydrogen pressure (P_H) was investigated for the case of a monolayer. This involved an increased enrichment in the Si of the deposited film, because of the incorporation deficit of oxygen that is efficiently "reduced" by hdrogen. This was found to favour the formation of Si crystallites, together with a significant improvement of the phase segregation between Si grains and silica. The increase of the deposition temperature (T_s) induced similar effects in such a way that the layer obtained with high P_H and T_s behaves as a pure silicon film with a refractive index cose to 3.2. Thus, a 40-period Si-rich/silica multilayered system was fabricated by alternating the introduction and the switching off of the hydrogen flux. The related electron microscopy image showed evidence of good quality multilayers, which attests the reliability of the new method.