METHOD OF FABRICATING CONDUCTIVE POLYSILICON AND SILICON METAL COUPLING STRUCTURE

摘要

A method and structure for polysilicon lines which include a silicide layer for providing a low sheet resistance. The invention may be employed in a polysilicon gate MOSFET process for integrated circuits as well as other integrated structures. In the method a first layer of polysilicon is deposited followed by a deposition of a metal of the silicide forming type. Another polysilicon layer is then deposited on top of the silicide forming metal to produce a three layer structure. The three layer structure is subjected to heat, for example, during the reoxidation step in a gate fabrication process, the metal reacts with the polysilicon at two reaction fronts to form a silicide. The resultant silicide has a much lower resistivity than doped polysilicon and therefore provides a second conductive layer which can be used more compatibly and efficiently in connection with the normal metal layer employed in integrated circuits to give a two-dimensional degree of freedom for the distribution of signals.