Sputtering method
A sputtering method of forming a thin film by allowing a target material to react with a gas includes narrowing down film deposition conditions from an existing period of nitrogen radicals by focusing on a nitriding process in thin-film forming processes when the thin film is formed by pulsing a waveform of electric current from a DC power supply at the time of generating plasma and applying the electric current to the target material.
1. A sputtering method of forming an amorphous nitride film, comprising:
determining pulsed electric current application conditions based on a pre-measured duration of nitrogen radicals generated from nitrogen gas by application of pulsed voltage;
providing a target material in a chamber;
supplying a nitrogen gas into the chamber;
generating a plasma by pulsing a waveform of electric current from a DC power supply with the nitrogen gas present in the chamber; and
applying the pulsed electric current to the target material to form the amorphous nitride film,
wherein the pulsed electric current application conditions include a pulse frequency of the waveform of the pulsed electric current within a range of 10 kHz to 50 kHz inclusive, a ratio of a period in which a voltage is applied in one pulse period within a range of 0.1% to 30% inclusive, a period in which the pulse is not applied within a range of 15 microseconds to 45 microseconds inclusive, and a sputtering pressure within a range of 0.1 Pa to 0.3 Pa inclusive.
2. The sputtering method according to claim 1 , wherein the pulse frequency is within a range of 20 kHz to 50 kHz inclusive.
3. The sputtering method according to claim 1 , wherein the ratio of the period in which the voltage is applied in one pulse period is within a range of 20% to 30% inclusive.
4. The sputtering method according to claim 1 , wherein target material is silicon to form the amorphous nitride thin film made of silicon nitride.
5. The sputtering method according to claim 1 , wherein the target material contains at least one of tantalum, niobium, chromium, aluminum and titanium.
6. The sputtering method according to claim 1 , wherein the chamber is a vacuum chamber, and the target material contains silicon.
7. The sputtering method according to claim 1 , further comprising arranging a magnet at a back surface of the target material, and generating a magnetic field on a surface of the target material with the magnet.