Method of depositing thin film
A method for forming a silicon germanium oxide thin film on a substrate in a reaction space may be performed using an atomic layer deposition (ALD) process. The process may include at least one cycle comprising a germanium oxide deposition sub-cycle and a silicon oxide deposition sub-cycle. The germanium oxide deposition sub-cycle may include contacting the substrate with a germanium reactant, removing excess germanium reactant, and contacting the substrate with a first oxygen reactant. The silicon oxide deposition sub-cycle may include contacting the substrate with a silicon reactant, removing excess silicon reactant, and contacting the substrate with a second oxygen reactant. The films of the present disclosure exhibit desirable etch rates relative to thermal oxide. Depending on the films' composition, the etch rates may be higher or lower than the etch rates of thermal oxide.
1. A method for forming a silicon germanium oxide thin film on a substrate in a reaction space by at least one complete cycle of an atomic layer deposition (ALD) process, wherein one complete cycle comprises:
a germanium oxide deposition sub-cycle comprising:
contacting the substrate with a germanium reactant,
removing excess germanium reactant, and
contacting the substrate with a first oxygen reactant; and
a silicon oxide deposition sub-cycle comprising:
contacting the substrate with a silicon reactant,
removing excess silicon reactant, and
contacting the substrate with a second oxygen reactant.
2. The method of claim 1 , wherein at least one of the first and second oxygen reactants comprises oxygen plasma.
3. The method of claim 2 , wherein the oxygen plasma is generated from a flowing oxygen source.
4. The method of claim 3 , wherein the oxygen source is flowed throughout the atomic layer deposition process.
5. The method of claim 3 , wherein the oxygen source is provided intermittently in the germanium oxide sub-cycle and the silicon oxide sub-cycle.
6. The method of claim 2 , wherein the oxygen source comprises oxygen gas.
7. The method of claim 1 , wherein for at least one complete cycle, the ratio of germanium oxide deposition sub-cycles to silicon oxide deposition sub-cycles is greater than or equal to about 1:1.
8. The method of claim 1 , wherein for at least one complete cycle, the ratio of germanium oxide deposition sub-cycles to silicon oxide deposition sub-cycles is less than or equal to about 1:1.
9. The method of claim 1 , wherein the ratio of the germanium oxide deposition sub-cycles to the silicon oxide deposition sub-cycles is selected such that the silicon germanium oxide thin film has a wet etch rate ratio of between 3 and 400 relative to thermal oxide.
10. The method of claim 1 , wherein for at least one complete cycle, the silicon oxide deposition sub-cycle precedes the germanium deposition sub-cycle.
11. The method of claim 1 , wherein the silicon germanium oxide film has a step coverage of at least about 95% on a three-dimensional structure with an aspect ratio of at least about 20:1.
12. The method of claim 1 , wherein the silicon germanium oxide film has a wet etch rate ratio relative to thermal oxide of less than about 4.
13. The method of claim 1 , wherein the silicon germanium oxide film achieves a wet etch rate ratio relative to thermal oxide of greater than about 20.
14. The method of claim 1 , wherein the deposition temperature is between about 450° C. and about 50° C.
15. The method of claim 1 , wherein the silicon reactant is selected from the the group consisting of (SiH 3 ) 3 N, (SiH 3 ) 2 , (SiH 3 ) 2 NMe, (SiH 3 ) 2 Net, (SiH 3 ) 2 N(iPr), (SiH 3 ) 2 N(tBu), SiH 3 NEt 2 , SiH 3 N(iPr) 2 , SiH 3 N(tBu) 2 , SiH 2 (NEt 2 ) 2 , SiH 2 (NMe 2 ) 2 , SiH 2 (NHtBu) 2 , SiH 2 (NHSiMe 3 ) 2 , Si(OEt) 4 , SiCl 4 , Si 2 Cl 6 , SiH 2 Cl 2 , SiH(N(Me) 2 ) 3 , SiH 2 [N(Et)(Me)] 2 , Si 2 (NHEt) 6 , Si(NHEt) 4 , and Si 3 H 8 .
16. The method of claim 1 , wherein the germanium reactant is selected from the group consisting of Ge(NMe 2 ) 4 , Ge(NEtMe) 4 ; Ge(NEt 2 ) 4 , iPr 3 GeCl, iPr 3 GeNMe 2 , iPr 3 GeNEtMe, and iPr 3 GeNEt 2 .
17. The method of claim 1 , wherein at least one of the first and second oxygen reactants is selected from the following list: O 2 , O 3 , NO, NO 2 , CO 2 , a plasma generated from one or more of these, or a combination thereof.
18. The method of claim 1 , wherein removing comprises flowing a purge gas through the reaction space.
19. The method of claim 1 , wherein the germanium reactant is Ge[N(CH 3 ) 2 ] 4 , the silicon reactant is SiH 2 [N(C 2 H 5 ) 2 ] 2 , and at least one of the first and second oxygen reactants comprises oxygen plasma.
20. A method for forming a silicon germanium oxide thin film on a substrate in a reaction space by performing a plurality of an atomic layer deposition (ALD) cycles, wherein at least one ALD cycle comprises:
at least one ALD germanium oxide deposition sub-cycle; and
at least one ALD silicon oxide deposition sub-cycle.
21. The method of claim 20 , wherein the at least ALD one germanium oxide deposition sub-cycle comprises:
contacting the substrate with a germanium reactant,
removing excess germanium reactant, and
contacting the substrate with a first oxygen reactant.
22. The method of claim 20 , wherein the at least one ALD silicon oxide deposition sub-cycle comprises:
contacting the substrate with a silicon reactant,
removing excess silicon reactant, and
contacting the substrate with a second oxygen reactant.
23. The method of claim 20 , wherein a ratio of the at least one germanium deposition sub-cycles to the at least one silicon deposition sub-cycles is greater than or equal to about 1:1.
24. The method of claim 20 , wherein a ratio of the at least one germanium deposition sub-cycles to the at least one silicon deposition sub-cycles is less than or equal to about 1:1.
25. The method of claim 20 , wherein a ratio of the at least one germanium oxide deposition sub-cycle to the at least one silicon oxide deposition sub-cycle is between about 1:20 and about 20:1.
26. The method of claim 20 , wherein an oxygen plasma is used in at least one of the at least one ALD germanium oxide deposition sub-cycle and the at least one ALD silicon oxide deposition sub-cycle.