Experimental study of the effects of showerhead configuration on large-area silicon-nitride thin film by plasma-enhanced chemical vapor deposition

Showerhead is a typical and important part in a vertical plasma-enhanced chemical vapor deposition (PECVD) reactor. A contrast experiment with the same recipe but different showerhead configurations was carried out, where the effects of the blocked area, position and drilling depth of the arrayed holes on the full-wafer deposition rate and the ratio of nitrogen to silicon of the silicon-nitride thin film were examined. The results of the blocking-hole scheme demonstrate that: the deposition rate is higher under the blocked region; the gradients of the deposition rate in the edge-opened configurations are larger than those in the center-opened configurations; the tendency of the ratio of nitrogen to silicon goes up towards to the centroid in the edge-opened configurations. The results of the drilling-hole scheme show a similar characteristic, however, the gradients are much smoother than those in the blocking-hole scheme. These results indicate that it is a feasible way to globally or locally refine the qualities of the large-area thin film through tailoring or varying the drilling depth of the arrayed holes on the showerhead face plate. This paper contributes to the structural design for the large-area silicon-nitride thin-film PECVD rector with vertical showerhead, and can also be referred to the other large-area thin-film reactor with multi-hole arrayed showerhead.