Selective deposition of metal silicides
Embodiments of the disclosure relate to selective metal silicide deposition methods. In one embodiment, a substrate having a silicon containing surface is heated and the silicon containing surface is hydrogen terminated. The substrate is exposed to sequential cycles of a MoF 6 precursor and a Si 2 H 6 precursor which is followed by an additional Si 2 H 6 overdose exposure to selectively deposit a MoSi x material comprising MoSi 2 on the silicon containing surface of the substrate. Methods described herein also provide for selective native oxide removal which enables removal of native oxide material without etching bulk oxide materials.
1. A substrate processing method, comprising:
exposing a silicon containing substrate comprising bulk silicon oxide and native silicon oxide to a plasma formed from an NF 3 precursor and an NH 3 precursor to selectively remove the native silicon oxide from the substrate, the exposing comprising:
heating the substrate to a temperature of between 40° C. and 50° C.; and
exposing the substrate to the plasma for a period of time less than 40 seconds;
heating the substrate to a first temperature;
exposing the substrate to a plasma comprising hydrogen;
exposing the substrate to a first dosage of a MoF 6 precursor;
exposing the substrate to a second dosage of a Si 2 H 6 precursor;
sequentially cycling the exposing the substrate to the first dosage and the exposing the substrate to the second dosage; and
after the sequential cycling, exposing the substrate to a third dosage of the Si 2 H 6 precursor.
2. The method of claim 1 , further comprising:
annealing the substrate after the exposing the substrate to the third dosage at a second temperature of between 500° C. and 550° C.
3. The method of claim 1 , wherein the first temperature is between 100° C. and 150° C.
4. The method of claim 1 , wherein the sequential cycling is performed less than 10 times.
5. The method of claim 4 , wherein the sequential cycling is performed 5 times.
6. The method of claim 1 , wherein the plasma comprising hydrogen is formed from precursors selected form the group consisting of NF 3 , NH 3 , and H.
7. The method of claim 1 , wherein a nitrogen purge process utilizing N 2 is performed during the sequential cycling.
8. The method of claim 1 , wherein the first dosage is performed for a duration of between 10 ms and 100 ms.
9. The method of claim 8 , wherein the first dosage comprises a MoF 6 flow rate of between 1 MegaL and 10 MegaL.
10. The method of claim 8 , wherein the second dosage is performed for a duration of between 1 ms and 50 ms.
11. The method of claim 10 , wherein the second dosage comprises a Si 2 H 6 flow rate of between 1 MegaL and 10 MegaL.
12. The method of claim 11 , wherein the third dosage comprises a Si 2 H 6 flow rate of between 20 MegaL and 50 MegaL.
13. The method of claim 12 , wherein the third dosage comprises between 3 pulses and 10 pulses of Si 2 H 6 .
14. The method of claim 1 , further comprising:
selectively depositing a MoSi x film on the silicon containing surface at a growth rate of 1.2 nm per sequential cycle.
15. A substrate processing method, comprising:
positioning a silicon containing substrate comprising bulk silicon oxide and native silicon oxide on a heater in a reaction chamber having chamber walls;
exposing the substrate to a plasma formed from an NF 3 precursor and an NH 3 precursor to selectively remove the native silicon oxide from the substrate, the exposing comprising:
heating the substrate to a temperature of between 40° C. and 50° C.; and
exposing the substrate to the plasma for a period of time less than about 40 seconds;
heating the substrate on the heater to a first temperature;
maintaining the chamber walls at a second temperature less than the first temperature;
exposing a silicon containing surface of the substrate to hydrogen;
exposing the substrate to a first dosage of a MoF 6 precursor;
exposing the substrate to a second dosage of a Si 2 H 6 precursor;
sequentially cycling the exposing the substrate to the first dosage and the exposing the substrate to the second dosage; and
after the sequential cycling, exposing the substrate to a third dosage of the Si 2 H 6 precursor.