Alternative gases and processes for amorphous and microcrystalline silicon etching

In amorphous and microcrystalline silicon technology, SF/sub 6/ is widely used in plasma etching processes, in particular for the cleaning of deposition chambers. Since SF/sub 6/ is known to cause adverse effects to the upper atmosphere, its replacement is of interest. Here, two approaches will be discussed. In one approach, the dilution of NF/sub 3/ with argon, neon, helium and nitrogen is explored for the purpose to increase the etch rate and/or to reduce the costs. High etching rates exceeding 100 /spl Aring//s and high NF/sub 3/ utilization were achieved for NF/sub 3//Ar gas mixtures at a load factor near unity. In the other approach, etching by hydrogen is investigated.