Method of forming conformal dielectric film having Si-N bonds by PECVD
A method of forming a conformal dielectric film having Si—N bonds on a semiconductor substrate by plasma enhanced chemical vapor deposition (PECVD) includes: introducing a nitrogen- and hydrogen-containing reactive gas and an additive gas into a reaction space inside which a semiconductor substrate is placed; applying RF power to the reaction space; and introducing a hydrogen-containing silicon precursor in pulses into the reaction space wherein a plasma is excited, thereby forming a conformal dielectric film having Si—N bonds on the substrate.
1. A method of forming a conformal dielectric film having Si—N bonds on a semiconductor substrate by plasma enhanced chemical vapor deposition (PECVD), which comprises:
introducing a nitrogen- and hydrogen-containing reactive gas and an additive gas into a reaction space inside which the semiconductor substrate is placed;
applying RF power to the reaction space; and
introducing a hydrogen-containing silicon precursor in pulses into the reaction space wherein a plasma is excited, thereby forming a conformal dielectric film having Si—N bonds on the substrate,
wherein the hydrogen-containing silicon precursor is introduced in pulses of a duration of approximately 0.1 sec to 1.0 sec with an interval between pulses of approximately 0.1 sec to 3.0 sec, while the reactive gas and the additive gas are continuously introduced, and the RF power is continuously applied.
2. The method according to claim 1 , wherein the hydrogen-containing silicon precursor has a formula of Si α H β X γ , wherein α, β and γ are integers (γ includes zero), wherein X comprises N, F and/or C m H n , wherein m and n are integers.
3. The method according to claim 2 , wherein the hydrogen-containing silicon precursor consists of Si, H, and N atoms constituting its molecule.
4. The method according to claim 1 , wherein the substrate is kept at a temperature of about 0° C. to about 400° C. while the film is deposited thereon.
5. The method according to claim 1 , wherein the hydrogen-containing silicon precursor is vaporized upstream of the reaction space.
6. The method according to claim 1 , wherein the hydrogen-containing precursor is a liquid at room temperature.
7. The method according to claim 1 , wherein the pulse duration is equal to or shorter than the interval between pulses.
8. The method according to claim 1 , wherein the reactive gas comprises at least one of a mixture of N 2 and H 2 , a mixture of NH 3 and H 2 , and a nitrogen-boron-hydrogen gas.
9. The method according to claim 8 , wherein the reactive gas comprises a mixture of N 2 and H 2 and has a molar flow rate ratio of N 2 /H 2 of approximately 1/1 to 10/1.
10. The method according to claim 8 , wherein the reactive gas comprises a mixture of NH 3 and H 2 and has a molar flow rate ratio of NH 3 /H 2 of approximately 1:1 to 1:10.
11. The method according to claim 1 , wherein the additive gas comprises a mixture of helium and argon or a mixture of helium and krypton.
12. The method according to claim 11 , wherein the additive gas is a mixture of helium and argon and has a molar flow rate ratio of helium/argon of approximately 3/1 to 20/1.
13. The method according to claim 11 , wherein the additive gas is a mixture of helium and krypton and has a molar flow rate ratio of helium/krypton of approximately 3/1 to 20/1.
14. The method according to claim 1 , wherein the conformal dielectric film is a silicon nitride film.
15. The method according to claim 1 , wherein the RF power is applied in the range of approximately 0.02 W/cm 2 to approximately 20 W/cm 2 per area of the substrate and a pressure in the reaction space is adjusted in the range of approximately 0.1 Torr to approximately 10 Torr.
16. The method according to claim 1 , wherein pulse durations and intervals of the pulses of introducing the hydrogen-containing silicon precursor are such that the conformal dielectric film has a step coverage or conformality of at least 80%.
17. The method according to claim 16 , wherein the pulse durations and intervals of the pulses of introducing the hydrogen-containing silicon precursor are such that the conformal dielectric film has an etching rate lower than thermal oxide film.
18. The method according to claim 16 , wherein the pulse durations and intervals of the pulses of introducing the hydrogen-containing silicon precursor are such that the conformal dielectric film has a leakage current lower than 1.0E-08 A/cm 2 at a 1 MV charge.
19. The method according to claim 1 , wherein the RF power is continuously applied.
20. The method according to claim 1 , wherein the pulse duration is from approximately 0.1 sec to about 0.3 sec.