Method for fabricating semiconductor device
A semiconductor device fabrication method by which the thermal stability of nickel silicide can be improved. Nickel (or a nickel alloy) is formed over a semiconductor substrate on which a gate region, a source region, and a drain region are formed. Dinickel silicide is formed by performing a first annealing step, followed by a selective etching step. By performing a plasma treatment step, plasma which contains hydrogen ions is generated and the hydrogen ions are implanted in the dinickel silicide or the gate region, the source region, and the drain region under the dinickel silicide. The dinickel silicide is phase-transformed into nickel silicide by performing a second annealing step.
1. A method for fabricating a semiconductor device, the method comprising:
the step of forming one of nickel and a nickel alloy over a semiconductor substrate on which a gate region, a source region, and a drain region are formed;
the first annealing step of forming dinickel silicide in the gate region, the source region, and the drain region by performing annealing treatment at a first temperature followed by a selective etching step to remove unreacted metal;
the plasma treatment step of generating plasma which contains hydrogen ions and implanting the hydrogen ions in one of the dinickel silicide, and the gate region, the source region, and the drain region under the dinickel silicide; and
the second annealing step of phase-transforming the dinickel silicide into nickel silicide by performing annealing treatment at a second temperature.
2. The method according to claim 1 , wherein the plasma treatment step is performed simultaneously with the second annealing step.
3. The method according to claim 1 , wherein the plasma comprises hydrogen plasma.
4. The method according to claim 1 , wherein the plasma comprises ammonia plasma.
5. The method according to claim 1 , wherein the plasma comprises one of diborane plasma, silane plasma, and disilane plasma.
6. The method according to claim 1 , wherein the hydrogen ions are implanted near an interface between the dinickel silicide and the gate region, the source region, and the drain region of the semiconductor substrate.
7. The method according to claim 3 , wherein the plasma treatment step is performed under the condition of 100 W to 750 W per 200-millimeter wafer.
8. The method according to claim 1 , wherein the nickel alloy contains at least one of platinum, tungsten, tantalum, and palladium.
9. The method according to claim 1 , wherein one of silicon-germanium compound crystals, silicon-carbon compound crystals, and silicon-germanium-carbon compound crystals is formed in one of the gate region, the source region, and the drain region of the semiconductor substrate.
10. The method according to claim 8 , wherein after a silicon layer is formed over one of the silicon-germanium compound crystals and the silicon-germanium-carbon compound crystals, one of the nickel and the nickel alloy is formed over the silicon layer.
11. The method according to claim 1 , wherein the second annealing step is performed in an atmosphere which contains silane.
12. The method according to claim 1 , wherein when the first annealing step is performed, the first temperature is set to 200° C. to 350° C. and annealing time is set to 10 seconds to 400 seconds.
13. The method according to claim 1 , wherein when the second annealing step is performed, the second temperature is set to 300° C. to 500° C. and annealing time is set to 10 seconds to 400 seconds.