Selective deposition of silicon nitride on silicon oxide using catalytic control
It will be understood that in some embodiments, nitrogen-containing ligands bonded to the silicon may not necessarily be identical to another nitrogen-containing ligand bonded to the same silicon atom. For example, in some embodiments, R 1 and R 2 may be different alkyl ligands. In some embodiments, a first NR 1 R 2 ligand attached to a silicon atom may not be the same as or have the same alkyl ligands as another NR 1 R 2 ligand attached to the same silicon atom. As noted above, R 1 and R 2 may be any alkyl ligand. In one example, the aminosilane may be N′N′-dimethylsilanediamine, having the structure:
1. A method of depositing silicon nitride selectively on an exposed silicon oxide surface of a substrate, the method comprising:
providing the substrate having the exposed silicon oxide surface and an exposed silicon surface;
exposing the substrate to trimethylaluminum to form an aluminum-containing moiety selectively on the exposed silicon oxide surface relative to the exposed silicon surface; and
performing one or more cycles of thermal atomic layer deposition, each cycle comprising exposing the substrate to an aminosilane precursor and exposing the substrate to a hydrazine without igniting a plasma to form silicon nitride selectively on the exposed silicon oxide surface relative to the exposed silicon surface,
wherein the hydrazine has a chemical structure of:
wherein R3, R4, R5, and R6 are each hydrogen or an alkyl group.
2. The method of claim 1 , further comprising periodically exposing the substrate to the trimethylaluminum every 20 to 40 cycles of the thermal atomic layer deposition.
3. The method of claim 1 , wherein, during the one or more cycles of thermal atomic layer deposition, the substrate resides on a pedestal set to a temperature between about 25° C. and about 400° C.
4. The method of claim 1 , wherein, during the one or more cycles of thermal atomic layer deposition, the substrate is disposed in a chamber having a chamber pressure between about 10 mTorr and about 10 Torr.
5. The method of claim 1 , wherein exposing the substrate to the trimethylaluminum comprises flowing the trimethylaluminum to a chamber housing the substrate at a flow rate between about 100 sccm and about 10,000 sccm.
6. The method of claim 1 , wherein the hydrazine is selected from the group consisting of t-butylhydrazine and tetramethyl hydrazine.
7. The method of claim 1 , wherein the aminosilane has a chemical formula
and wherein x is an integer between and including 1 and 3, x+y=4 and each of R1 and R2 is hydrogen or an alkyl group.
8. The method of claim 7 , wherein the aminosilane is selected from the group consisting of monoaminosilane, diaminosilane, triaminosilane, tetraaminosilane, N′N′ dimethylsilanediamine, and combinations thereof.
9. The method of claim 1 , wherein the substrate is disposed in a chamber and each cycle further comprises purging the chamber between exposing the substrate to the aminosilane precursor and exposing the substrate to the hydrazine without igniting a plasma.
10. The method of claim 4 , wherein the chamber pressure is between about 1 Torr and about 3 Torr.
11. The method of claim 1 , wherein, during the exposing the substrate to the trimethylaluminum, the substrate is disposed in a chamber having a chamber pressure between about 10 mTorr and about 10 Torr.
12. The method of claim 3 , wherein the temperature is between about 200° C. and about 300° C.
13. The method of claim 1 , wherein, during the exposing the substrate to the trimethylaluminum, the substrate resides on a pedestal set to a temperature between about 25° C. and about 400° C.
14. The method of claim 1 , wherein the substrate is disposed in a chamber and chamber pressure during the exposing the substrate to the trimethylaluminum is the same as the chamber pressure during the one or more cycles of thermal atomic layer deposition.
15. The method of claim 1 , wherein the substrate resides on a pedestal having the same temperature during the exposing the substrate to the trimethylaluminum as during the one or more cycles of thermal atomic layer deposition.
16. The method of claim 1 , wherein the exposed silicon oxide surface comprises hydroxyl end groups.
17. The method of claim 1 , wherein the exposing the substrate to the trimethylaluminum is performed without igniting a plasma.