Semiconductor integrated circuit device and process for producing the same
Formation of an WN x film 24 constituting a barrier layer of a gate electrode 7 A having a polymetal structure is effected in an atmosphere containing a high concentration nitrogen gas, whereby release of N (nitrogen) from the WN x film 24 is suppressed in the heat treatment step after the formation of the gate electrode 7 A.
1. A semiconductor integrated circuit device comprising:
(a) a semiconductor integrated circuit chip having a first main surface;
(b) a silicon-base surface region, over the first main surface, having silicon as one of principal constituents;
(c) a gate insulating film over the silicon-base surface region;
(d) a first silicon-base polycrystalline film, over the gate insulating film, having silicon as one of principal constituents;
(e) a second silicon-base polycrystalline film disposed over the first silicon-base polycrystalline film, having a smaller average crystal size than the first silicon-base polycrystalline film, and having silicon as one of principal constituents;
(f) a tungsten suicide layer, over the second silicon-base polycrystalline film, having tungsten suicide as a principal component;
(g) a tungsten nitride film disposed over the tungsten silicide layer, containing W 2 N, having a thickness of 1 nm or greater and having a nitrogen content of 7% or greater; and
(h) a refractory metal film, over the nitride film, which is thicker than the tungsten silicide layer and has tungsten or molybdenum as a principal component.
2. A semiconductor integrated circuit device according to claim 1 , wherein the nitride film has a nitrogen content of 10% or greater.
3. A semiconductor integrated circuit device according to claim 2 , wherein the nitride film has a nitrogen content of 13% or greater.
4. A semiconductor integrated circuit device according to claim 3 , wherein the nitride film has a nitrogen content of 18% or greater.
5. A semiconductor integrated circuit device according to claim 1 , wherein the first silicon-base polycrystalline film partially contains germanium.
6. A semiconductor integrated circuit device according to claim 1 , wherein the second silicon-base polycrystalline film partially contains germanium.