| 摘要 |
PURPOSE: To independently control the thickness of nitride and that of silicide which are formed by heat treatment in a contact aperture, by delaying the growth of a silicide contact region which is replaced by a silicide region during a heat cycle, and controlling the thickness of the silicide contact region to a metallurgical barrier. CONSTITUTION: During a second heat cycle, movement of silicon, i.e., diffusion from a region 10 or 12, or a silicide region 52 of titanium to a layer 42 is hindered by the existence of a titanium nitride layer 50. The silicide region 52 of titanium formed during a first heat cycle is limited in a region below the layer 50. The titanium nitride layer 50 which is firstly formed during the second heat cycle functions as a metallurgical barrier in such a manner that all the second titanium layer 40 is completely transformed into the titanium nitride layer 52. Thereby the final total thickness of titanium nitride can be controlled. The final thickness of silicide layer 52 of titanium is mainly determined by the thickness of the firstly formed titanium layer 24. The final thickness of titanium nitride is determined by the thickness of both stuck titanium layers.
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