Electrode structure and method for fabricating the same

1. A method for fabricating a gate electrode structure comprising the steps of:

forming a silicon-containing film containing silicon as a principal constituent;

forming, on said silicon-containing film, a barrier metal layer of titanium nitride rich in titanium as compared with a stoichiometric ratio;

forming a metal film with a high melting point on said barrier metal layer, whereby forming a multi-layer film including said silicon-containing film, said barrier metal layer and said metal film with a high melting point; and

patterning said multi-layer film into said gate electrode structure,

wherein said gate electrode structure is formed on a gate insulating film,

wherein said step of forming said barrier metal layer includes a sub-step of using a target of titanium nitride rich in titanium as compared with a stoichiometric ratio and causing discharge in an inert gas including substantially no nitrogen, thereby depositing, on said silicon-containing film, the titanium nitride rich in titanium as compared with the stoichiometric ratio sputtered out from said target.

2. A method for fabricating a gate electrode structure comprising the steps of:

forming a silicon-containing film containing silicon as a principal constituent;

forming, on said silicon-containing film, a barrier metal layer of titanium nitride rich in titanium as compared with a stoichiometric ratio;

forming a metal film with a high melting point on said barrier metal layer, whereby forming a multi-layer film including said silicon-containing film, said barrier metal layer and said metal film with a high melting point; and

patterning said multi-layer film into electrode structure,

wherein said gate electrode structure is formed on a gate insulating film,

wherein the step of forming said barrier metal layer includes a sub-step of using a target of titanium including substantially no nitrogen and causing discharge in a mixed gas of a nitrogen gas and an inert gas with a partial pressure ratio of the nitrogen gas lower than a nitriding point of said target, thereby depositing, on said silicon-containing film, titanium nitride rich in titanium as compared with a stoichiometric ratio formed through a reaction between titanium sputtered out from said target and nitrogen ions included in said mixed gas.

3. A method for fabricating a gate electrode structure comprising the steps of:

forming a silicon-containing film containing silicon as a principal constituent;

forming, on said silicon-containing film, a barrier metal layer of titanium nitride rich in titanium as compared with a stoichiometric ratio;

forming a metal film with a high melting point on said barrier metal layer, whereby forming a multi-layer film including said silicon-containing film, said barrier metal layer and said metal film with a high melting point; and

patterning said multi-layer film into an electrode structure,

wherein said barrier metal layer is a diffusion preventing film for preventing impurities introduced into said silicon-containing film from diffusing to said metal film with a high melting point, and

no titanium silicide layer is formed on said silicon-containing film through annealing carried out on said electrode structure at a temperature of 600° C. or more.

4. The method for fabricating a gate electrode structure of claim 3 , wherein said step of patterning said multi-layer film includes a sub-step of patterning said silicon-containing film and said metal film with a high melting point into an equal pattern size.

5. The method for fabricating a gate electrode structure of claim 3 , wherein said ratio of nitrogen (ratio of Ni/Ti) included in said barrier metal layer is approximately 0.7.

6. A method for fabricating a gate electrode structure comprising the steps of:

forming a silicon-containing film containing silicon as a principal constituent;

forming, on said silicon-containing film, a first barrier metal layer of titanium nitride rich in titanium as compared with a stoichiometric ratio;

forming, on said first barrier metal layer, a second barrier metal layer of titanium nitride including nitrogen in a ratio not less than a stoichiometric ratio;

forming a metal film with a high melting point on said second barrier metal layer, whereby forming a multi-layer film including said silicon-containing film, said first barrier metal layer, said second barrier metal layer and said metal film with a high melting point; and

patterning said multi-layer film into said gate electrode structure,

wherein said gate electrode structure is formed on a gate insulating film,

wherein the step of forming said first barrier metal layer includes a sub-step of using a target of titanium nitride rich in titanium as compared with a stoichiometric ratio and causing discharge in an inert gas included in an inert gas including substantially no nitrogen, thereby depositing, on said silicon-containing film, the titanium nitride rich in titanium as compared with the stoichiometric ratio sputtered out from said target, and

the step of forming said second barrier metal layer includes a sub-step of using said target and causing discharge in a mixed gas of a nitrogen gas and an inert gas with a partial pressure ratio of the nitrogen gas not less than a nitriding point of said target, thereby forming, on said target, a titanium nitride film rich in titanium as compared with the stoichiometric ratio and depositing, on said first barrier metal layer, the titanium nitride rich in titanium as compared with the stoichiometric ratio sputtered out from said titanium nitride film formed on said target.

7. A method for fabricating a gate electrode structure comprising the steps of:

forming silicon-containing film containing silicon as a principal constituent;

forming, on said silicon-containing film, a first barrier metal layer of titanium nitride rich in titanium as compared with a stoichiometric ratio;

forming, on said first hairier metal layer, a second barrier metal layer of titanium nitride including nitrogen in a ratio not less than a stoichiometric ratio;

forming a metal film with a high melting point on said second barrier metal layer, whereby forming a multi-layer film including said silicon-containing film, said first barrier metal layer, said second barrier metal layer and said metal film with a high melting point; and

patterning said multi-layer film into said gate electrode structure,

wherein said gate electrode structure is formed on a gate insulating film,

wherein the step of forming said first barrier metal layer includes a sub-step of using a target including substantially no nitrogen and causing discharge in a mixed gas of a nitrogen gas and an inert gas with a partial pressure ratio of the nitrogen gas lower than a nitriding point of said target, thereby depositing, on said silicon-containing film, titanium nitride rich in titanium as compared with a stoichiometric ratio formed through a reaction between titanium sputtered out from said target and nitrogen ions included in said mixed gas, and

the step of forming said second barrier metal layer includes a sub-step of using said target and causing discharge in a mixed gas of a nitrogen gas and an inert gas with a partial pressure ratio of the nitrogen gas not less than the nitriding point of said target, thereby forming, on said target, a titanium nitride film rich in titanium as compared with a stoichiometric ratio and depositing, on said first barrier metal layer, the titanium nitride rich in titanium as compared with the stoichiometric ratio sputtered out from said titanium nitride film formed on said target.

8. A method for fabricating a gate electrode structure comprising the steps of:

forming a silicon-containing film containing silicon as a principal constituent;

forming, on said silicon-containing film, a first barrier metal layer of titanium nitride rich in titanium as compared with a stoichiometric ratio;

forming, on said first barrier metal layer, a second barrier metal layer of titanium nitride including nitrogen in a ratio not less than a stoichiometric ratio;

forming a metal film with a high melting point on said second barrier metal layer, whereby forming a multi-layer film including said silicon-containing film, said first barrier metal layer, said second barrier metal layer and said metal film with a high melting point; and

patterning said multi-layer film into an electrode structure,

wherein said first barrier metal layer and said second barrier metal layer are diffusion preventing films for preventing impurities introduced into said silicon-containing film from diffusing to said metal film with a high melting point, and

no titanium silicide layer is fanned on said silicon-containing film through annealing carried out on said electrode structure at a temperature of 600° C. or more.

9. The method for fabricating a gate electrode structure of claim 8 , wherein said step of patterning said multi-layer film includes a sub-step of patterning said silicon-containing film and said metal film with a high melting point into an equal pattern size.

10. The method for fabricating a gate electrode structure of claim 8 , wherein said ratio of nitrogen (ratio of N/Ti) included in said first barrier metal layer is approximately 0.7.