Anisotropic Etching of MoSi2 and Its Application to 2 μm Devices

There is a clear trend toward increment of packing density in the integrated circuit technologies. The extensibility of application of poly-Si to VLSI is limited by its relatively high sheet resistance. Refractory metal silicides have been proposed as an alternative material to poly-Si. In particular , MoSi₂ and WSi have been studied for the applications io the gate material and the interconnecting material. The double layer structure which forms a metallic silicide layer on poly-Si combines the advantages of a well-known and characterized SiO₂ to poly- Si interface with a low resistivity of silicide. It is, however, not easy to etch this double layer of silicide/poly-si without undesirable over-hanging.