Method and system for forming a silicon oxycarbide layer and structure formed using same
Methods of forming a silicon oxycarbide layer on a surface of a substrate are disclosed. Exemplary methods include providing an oxygen-free reactant to a reaction chamber and performing one or more deposition cycles, wherein each deposition cycle includes providing a silicon precursor to the reaction chamber for a silicon precursor pulse period and providing pulsed plasma power for a plasma power period to form the silicon oxycarbide layer.
1. A method of forming a silicon oxycarbide layer on a surface of a substrate, the method comprising the steps of:
providing a substrate within a reaction chamber of a reactor;
providing an oxygen-free reactant to the reaction chamber; and
performing one or more deposition cycles, wherein each deposition cycle comprises:
providing a silicon precursor to the reaction chamber for a silicon precursor pulse period, the silicon precursor comprising at least one oxygen atom per molecule; and
providing a pulsed plasma power to an electrode for a plasma power period to form a plasma within the reactor during the plasma power period,
wherein a plasma pulse period during the plasma power period is between about 0.01 and 0.2 msec,
wherein providing the pulsed plasma power produces a plasma having a reduced plasma potential, compared to a plasma formed by providing a same plasma power to the electrode without pulsing the plasma power,
wherein a dielectric constant of the silicon oxycarbide layer is less than 4.5, and
wherein a wet etch rate of the silicon oxycarbide layer in 0.5% dilute hydrofluoric acid is less than 1 nm/minute.
2. The method of claim 1 , wherein the oxygen-free reactant comprises one or more of argon (Ar) and hydrogen (H 2 ).
3. The method of claim 1 , wherein the oxygen-free reactant comprises 100 to about 90 volumetric percent argon (Ar).
4. The method of claim 1 , wherein the oxygen-free reactant comprises 0 to about 10 volumetric percent hydrogen (H 2 ).
5. The method of claim 1 , wherein the oxygen-free reactant comprises a mixture comprising argon (Ar) and hydrogen (H 2 ).
6. The method of claim 1 , wherein a duration of the plasma power period is between 0.01 and 5.0 seconds.
7. The method of claim 1 , wherein a plasma power on-time duty cycle is greater than 0 and less than 75%.
8. The method of claim 1 , wherein a plasma power on-time duty cycle is between about 10 and about 50%.
9. The method of claim 1 , wherein the molecule comprises one or more Si—C bonds.
10. The method of claim 1 , wherein the silicon precursor is represented by the formula: (R i ) 4-x Si(O—R i ) x , where x can be between 1 and 3, (R i —O—R ii ) 4-x Si(O—R i ) x , where x can be between 1 and 3 and (R i 3-x Si(O—R i ) x )—R ii —(R i 3-x Si(O—R i ) x ), where x can be between 1 and 3, Wherein R i is an independently selected alkyl group and R ii is an independently selected hydrocarbon.
11. The method of claim 1 , wherein the silicon precursor comprises one or more of 1,2-bis(triethoxysilyl)ethane (BTESE),), dimethoxymethylvinylsilane (DMOMVS), 1,2-bis(methyldiethoxysilyl)ethane (BMDESE), and (3-methoxypropyl)trimethoxysilane (MPTMS).
12. The method of claim 1 , wherein the silicon oxycarbide layer forms a spacer.
13. The method of claim 1 , wherein the dielectric constant of the silicon oxycarbide layer is less than 4.25.
14. The method of claim 1 , wherein the wet etch rate of the silicon oxycarbide layer in 0.5% dilute hydrofluoric acid is less than 0.8 nm/minute.
15. The method of claim 1 , wherein the reactant is continuously provided to the reaction chamber during a deposition cycle of the one or more deposition cycles.
16. The method of claim 1 , wherein the reactant is continuously provided to the reaction chamber during two or more deposition cycles.
17. The method of claim 1 , wherein the silicon precursor pulse period ceases prior to the plasma power period.
18. The method of claim 1 , wherein a duration of the silicon precursor pulse period is between about 0.1 and about 2.0 seconds.
19. The method of claim 1 , wherein a temperature of the substrate is between about 100 and about 550° C.
20. The method of claim 1 , wherein a pressure within the reaction chamber during the deposition cycle is about 200 and about 3000 Pa.