Integrated circuit structure having intermediate metal silicide layer

Abstract

An improved integrated circuit structure characterized by enhanced step coverage and a method of making it are disclosed. The structure comprises a base layer of silicon, a first oxide layer on the silicon layer, strips of poly silicon having selected portions thereof reacted with a metal capable of forming a metal silicide in situ on the surface of the poly silicon strips, a further oxide layer over the metal silicide, and a metal layer providing electrical contact to selected portions of the structure. The construction makes it possible to remove all of an intermediate oxide layer during manufacture except for an oxide layer above the poly load resistor. This elimination of one oxide layer, together with the integration of the conductive metal silicide and underlying poly silicon into one layer and the rounding of the metal silicide edge with oxide spacers via anisotropic etching of the intermediate oxide layer, permits better step coverage for the resulting structure.