Method for fabricating semiconductor device in which threshold voltage shift and charge-pumping current are improved

Said method for fabricating a semiconductor device on a silicon substrate, comprising the steps of:

• a) forming a silicon oxide film on the silicon substrate;
• b) forming a silicon nitride film on the silicon oxide film;
• c) thermally nitriding the silicon nitride film in an atmosphere of nitrogenous gas;
• d) oxidizing the silicon nitride film nitrided in the step c);
• e) forming a conductive film on the silicon nitride film oxidized in the step d);
• f) forming a gate region from the silicon oxide film formed in the step a), the silicon nitride film oxidized in the step d), and the conductive film formed in the step e), a channel region being positioned under the gate region in the silicon substrate;
• g), forming a source region in the silicon substrate adjacent to one side of the channel region;
• h) forming a drain region in the silicon substrate adjacent to another side of the channel region;
• and
• i) forming wiring regions on the source region, the drain region, and the gate region, the semiconductor device being fabricated by the gate region, the channel region, the source region, the drain region, and the wiring regions.

A method for fabricating a semiconductor device on a silicon substrate, comprising the steps of:

• a) forming a silicon oxide film on the silicon substrate;
• b) forming a silicon nitride film on the silicon oxide film;
• c) annealing the silicon nitride film in an atmosphere of argon gas;
• d) forming a conductive film on the silicon nitride film annealed in the atmosphere of argon gas;
• e) forming a gate region from the silicon oxide film formed in the step a), the silicon nitride film annealed in the step c), and the conductive film formed in the step d), a channel region being positioned under the gate region in the silicon substrate;
• f) forming a source region in the silicon substrate adjacent to one side of the channel region;
• g) forming a drain region in the silicon substrate adjacent to another side of the channel region;
• and
• h) forming wiring regions on the source region, the drain region, and the gate region, the semiconductor device being fabricated by the gate region, the channel region, the source region, the drain region, and the wiring regions.

A method for fabricating a semiconductor device on a silicon substrate, comprising the steps of:

• a) forming a silicon oxide film on the silicon substrate;
• b) forming a silicon nitride film on the silicon oxide film;
• c) annealing the silicon nitride film in an atmosphere of argon gas;
• d) oxidizing the annealed silicon nitride film;
• e) forming a conductive film on the silicon nitride film oxidized in the step d);
• f) forming a gate region from the silicon oxide film formed in the step a), the silicon nitride film oxidized in the step d), and the conductive film formed in the step e), a channel region being positioned under the gate region in the silicon substrate;
• g) forming a source region in the silicon substrate adjacent to one side of the channel region;
• h) forming a drain region in the silicon substrate adjacent to another side of the channel region;
• and
• i) forming wiring regions on the source region, the drain region, and the gate region, the semiconductor device being fabricated by the gate region, the channel region, the source region, the drain region, and the wiring regions.

A method for fabricating a semiconductor device on a silicon substrate, comprising the steps of:

• a) forming a silicon oxide film on the silicon substrate;
• b) forming a silicon nitride film on the silicon oxide film;
• c) thermally nitriding the silicon nitride film in an atmosphere of nitrogenous gas;
• d) forming a conductive film on the silicon nitride film nitrided in the atmosphere of the nitrogenous gas;
• and
• e) forming a gate region from both the silicon oxide film formed in the step a) and the silicon nitride film nitrided in the step c), a channel region being positioned under the gate region in the silicon substrate and the semiconductor device being fabricated by the gate region and the channel region.

A method for fabricating a semiconductor device on a silicon substrate, comprising the steps of:

• a) forming a silicon oxide film on the silicon substrate;
• b) thermally nitriding the silicon oxide film in an atmosphere of nitrogenous gas by a rapid thermal nitridation method to form an interface region in which the nitrogen concentration is between 0.2 atomic % and 1.0 atomic %, the interface region being positioned between the silicon oxide film and the silicon substrate;
• c) forming a conductive film on the silicon oxide film;
• d) forming a gate region from both the silicon oxide film nitrided in the step b) and the conductive film formed in the step c), a channel region being formed under the gate region in the silicon substrate;
• e) forming a source region in the silicon substrate adjacent to one side of the channel region;
• f) forming a drain region in the silicon substrate adjacent to another side of the channel region;
• and
• g) forming wiring regions on the source region, the drain region, and the gate region, the semiconductor device being fabricated by the gate region, the channel region, the source region, the drain region, and the wiring regions.

A method for fabricating a semiconductor device on a silicon substrate, comprising the steps of:

• a) forming a silicon oxide film on the silicon substrate;
• b) thermally nitriding the silicon oxide film in an atmosphere of nitrogenous gas by a rapid thermal nitridation method and re-oxidizing the silicon oxide film in an atmosphere of oxygen gas so as to form an interface region in which the nitrogen concentration is between 0.2 atomic % and 1.0 atomic %, the interface region being positioned between the silicon oxide film and the silicon substrate;
• c) forming a conductive film on the silicon oxide film;
• d) forming a gate region from both the silicon oxide film nitrided and re-oxidized in the step b) and the conductive film formed in the step c), a channel region being formed under the gate region in the silicon substrate;
• e) forming a source region in the silicon substrate adjacent to one side of the channel region;
• f) forming a drain region in the silicon substrate adjacent to another side of the channel region;
• and
• g) forming wiring regions on the source region, the drain region, and the gate region, the semiconductor device being fabricated by the gate region, the channel region, the source region, the drain region, and the wiring regions.

A method for fabricating a semiconductor device on a silicon substrate, comprising the steps of:

• a) forming a silicon oxide film on the silicon substrate by a liquid phase deposition method;
• b) densifying the silicon oxide film by vaporizing water included in the silicon oxide film;
• c) thermally nitriding the silicon oxide film densified in the step b);
• d) re-oxidizing the surface of the nitrided silicon oxide film in an atmosphere of dry oxygen at temperatures around 1100.degree. C.;
• e) forming a conductive film on the re-oxidized silicon nitride film;
• f) forming a gate region from both the silicon oxide film formed in the step a) and the conductive film formed in the step c), a channel region being positioned under the gate region in the silicon substrate;
• g) forming a source region in the silicon substrate adjacent to one side of the channel region;
• h) forming a drain region in the silicon substrate adjacent to another side of the channel region;
• and
• i) forming wiring regions on the source region, the drain region, and the gate region, the semiconductor device being fabricated by the gate region, the channel region, the source region, the drain region, and the wiring regions.