ALD of metal silicate films

• US 20080020593A1
• Filed: 07/21/2006
• Published: 01/24/2008
• Est. Priority Date: 07/21/2006
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Shero, Eric J., Maes, Jan Willem, Wilk, Glen, Wang, Chang-gong
• Granted Patent: US 7,795,160 B2
• Time in Patent Office: Days
• US Class Current: 438/782
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions
• CPC Class Codes: H01L 21/02148 the material containing hafnium, e.g. HfSiOx or HfSiON
• CPC Class Codes: H01L 21/02159 the material containing zirconium, e.g. ZrSiOx
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/31612 on a silicon body
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2

Abstract

Methods for forming metal silicate films are provided. The methods comprise contacting a substrate with alternating and sequential vapor phase pulses of a metal source chemical, a silicon source chemical and an oxidizing agent. In preferred embodiments, an alkyl amide metal compound and a silicon halide compound are used. Methods according to preferred embodiments can be used to form hafnium silicate and zirconium silicate films with substantially uniform film coverages on substrate surfaces comprising high aspect ratio features (e.g., vias and/or trenches).

Claims

1. An atomic layer deposition (ALD) method for forming a metal silicate film, the method comprising alternately contacting a substrate in a reaction space with vapor phase pulses of an alkyl amide metal compound, a silicon halide compound and an oxidizing agent.

2. The method of claim 1, wherein the substrate is sequentially contacted with the alkyl amide metal compound, the oxidizing agent and the silicon halide compound.

3. The method of claim 1, wherein the substrate is sequentially contacted with the silicon halide compound, the oxidizing agent and the alkyl amide metal compound.

4. The method of claim 1, wherein the alkyl amide metal compound is selected from the group consisting of tetrakis(ethylmethylamino)metal, tetrakis(diethylamino)metal and tetrakis(dimethylamino)metal.

5. The method of claim 1, wherein the metal silicate film to be formed comprises one or both of hafnium (Hf) and zirconium (Zr).

6. The method of claim 1, wherein the silicon halide compound is silicon tetrachloride (SiCl₄).

7. The method of claim 1, wherein the oxidizing agent is selected from the group consisting of water, ozone and plasma-excited species of molecular oxygen (O₂).

8. The method of claim 1, further comprising purging the reaction space between each of said vapor phase pulses.

9. The method of claim 8, wherein the reaction space is purged with one or more gases selected from the group consisting of argon (Ar), nitrogen (N₂), helium (He) and hydrogen (H₂).

10. The method of claim 1, further comprising removing excess metal compound, silicon compound and oxidizing agent with the aid of a pumping system.

11. The method of claim 1, wherein the metal silicate film is formed at a substrate temperature between about 150°

C. and 500°

C.

12. The method of claim 11, wherein the metal silicate film is formed at a substrate temperature between about 250°

C. and 350°

C.

13. The method of claim 1, wherein the metal silicate film is used in a dynamic random access memory (DRAM) device.

14. The method of claim 1, wherein the metal silicate film is used as a gate dielectric in a complementary metal oxide semiconductor (CMOS) device.

15. The method of claim 1, wherein the metal silicate film is used as a component of a capacitor-based device.

16. An atomic layer deposition (ALD) process for forming a metal silicate film on a substrate in a reaction space, comprising:

(a) contacting the substrate with a vapor phase pulse of an alkyl amide metal compound;

(b) removing excess alkyl amide metal compound and reaction by-products from the reaction space;

(c) contacting the substrate with a vapor phase pulse of a first oxidizing agent;

(d) removing excess first oxidizing agent and reaction by-products from the reaction space;

(e) contacting the substrate with a vapor phase pulse of a silicon halide compound;

(f) removing excess silicon halide compound and reaction by-products from the reaction space;

(g) contacting the substrate with a vapor phase pulse of a second oxidizing agent;

(h) removing excess second oxidizing agent and reaction by-products from the reaction space; and

(i) repeating steps (a) through (h) until a metal silicate film of a desired thickness is formed over the substrate.

17. The method of claim 16, wherein formation of the metal silicate film begins with step (a) or step (e).

18. The method of claim 16, wherein steps (a) through (d) are repeated a desired number of times prior to steps (e) through (h).

19. The method of claim 16, wherein steps (e) through (h) are repeated a desired number of times after steps (a) through (d).

20. The method of claim 16, wherein the first oxidizing agent is the same as the second oxidizing agent.

21. The method of claim 16, wherein the first and second oxidizing agents are selected from the group consisting of water, ozone and plasma-excited species of molecular oxygen (O₂).

22. The method of claim 16, wherein the first oxidizing agent comprises one of water, ozone and plasma-excited species of molecular oxygen (O₂), and the second oxidizing agent is different from the first oxidizing agent.

23. The method of claim 16, wherein removing comprises purging the reaction space with an inert gas and/or pumping the reaction space with the aid of a pumping system.

24. The method of claim 16, wherein steps (a)-(d) form a metal oxide selected from the group consisting of hafnium oxide and zirconium oxide.

25. The method of claim 16, wherein steps (e)-(h) form a silicon oxide selected from the group consisting of SiO and SiO₂.

26. A hafnium silicate film comprising carbon and halogen impurities, wherein the carbon impurity concentration is less than or equal to about 50,000 parts-per-million (ppm) and the halogen impurity concentration is less than or equal to about 20,000 ppm, and wherein the hafnium silicate film has a step coverage greater than or equal to about 85%.

27. The hafnium silicate of claim 26, wherein the step coverage is about 100%.

28. The hafnium silicate of claim 26, wherein the carbon impurity concentration is less than or equal to about 10,000 ppm.

29. The hafnium silicate of claim 26, wherein the halogen impurity concentration is less than or equal to about 2,000 ppm.

30. The hafnium silicate film of claim 26, wherein the hafnium silicate film is part of a dynamic random access memory (DRAM) device.

31. The hafnium silicate film of claim 26, wherein the hafnium silicate film is part of a gate dielectric in a complementary metal oxide semiconductor (CMOS) device.