DOPING WITH ALD TECHNOLOGY

• US 20090214767A1
• Filed: 02/27/2008
• Published: 08/27/2009
• Est. Priority Date: 03/06/2001
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM America Incorporated (ASM International NV)
• Inventors: Shero, Eric, Wang, Chang-gong
• Granted Patent: US 9,139,906 B2
• Time in Patent Office: Days
• US Class Current: 427/126.100
• CPC Class Codes: C23C 16/45534 Use of auxiliary reactants other than used for contributing to the composition of the main film, e.g. catalysts, activators or scavengers
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28088 the final conductor layer next to the insulator being a composite, e.g. TiN
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/3115 Doping the insulating layers
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/3143 composed of alternated layers or of mixtures of nitrides and oxides or of oxinitrides, e.g. formation of oxinitride by oxidation of nitride layers
• CPC Class Codes: H01L 21/3162 on a silicon body
• CPC Class Codes: H01L 21/31641 Deposition of Zirconium oxides, e.g. ZrO2
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2
• CPC Class Codes: H01L 29/4966 the conductor material next to the insulator being a composite material, e.g. organic material, TiN, MoSi2 H01L29/4908, H01L29/4983 take precedence
• CPC Class Codes: H01L 29/518 the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material

Abstract

Methods for doping a substrate surface or the interface between two thin films by atomic layer deposition process (ALD) are provided. By blocking some of the available binding sites for a dopant precursor with a blocking reactant, the concentration and uniformity of dopant deposited can be controlled. The blocking reactant may be introduced prior to introduction of the dopant precursor in the ALD process, or the blocking reactant and the dopant precursor can be introduced simultaneously.

Claims

1. A method for doping the interface between two films on a substrate with a sub-monolayer of dopant comprising:

depositing a sub-monolayer of dopant on a first film on the substrate by a single atomic layer deposition cycle comprising;

contacting the substrate with a first reactant that is a blocking reactant such that the blocking reactant adsorbs in a self-limiting manner on the first film;

removing excess blocking reactant from the reaction space;

contacting the substrate with a second reactant that is a dopant precursor such that the dopant precursor adsorbs in a self limiting manner on the surface of the first film;

removing excess dopant precursor; and

contacting the substrate with a third reactant that reacts with

the dopant precursor to form a dopant on the first film; and

subsequently depositing a second thin film over the dopant,

wherein the blocking reactant and dopant precursor are selected such that a desired concentration of dopant is deposited on the first film.

2. The method of claim 1, wherein the dopant precursor is a metal source chemical.

3. The method of claim 2, wherein the metal source chemical is a transition metal source chemical.

4. The method of claim 3, wherein the metal source chemical comprises a metal selected from the group consisting of Ti, Hf, Zr, Si, Al, Ta, Sr, Ba, Sc, Y, La, Eu, and Dy.

5. The method of claim 4, wherein the metal source chemical is a hafnium halide.

6. The method of claim 5, wherein the metal halide source chemical is HfCl₄.

7. The method of claim 4, wherein the metal source chemical is a zirconium halide.

8. The method of claim 7, wherein the metal source chemical is ZrCl₄.

9. The method of claim 1, wherein the blocking reactant is a metal source chemical.

10. The method of claim 9, wherein the blocking reactant is trimethyl aluminum.

11. The method of claim 1, wherein the blocking reactant is a silicon source chemical.

12. The method of claim 11, wherein the silicon source chemical is a silicon halide.

13. The method of claim 12, wherein the silicon source chemical is SiCl₄.

14. The method of claim 1, wherein the third reactant is selected from the group consisting of H₂O, O₃, O radicals, H₂O₂ and D₂O.

15. The method of claim 1, further comprising providing an initial surface termination on the substrate prior to contacting the substrate with the blocking reactant.

16. The method of claim 1, wherein the substrate is contacted with the blocking reactant and the dopant precursor simultaneously.

17. The method of claim 1, wherein the substrate is contacted with the blocking reactant prior to being contacted with the dopant precursor

18. The method of claim 1, wherein the substrate is contacted with the blocking reactant multiple times prior to being contacted with the dopant precursor

19. A method for doping an interface between a dielectric thin film and a gate electrode comprising:

depositing a dielectric thin film on a substrate in a reaction space;

depositing hafnium on the surface of the dielectric thin film by a single-cycle atomic layer deposition process; and

after depositing the hafnium depositing a gate electrode over the dielectric thin film, wherein the single-cycle ALD process comprises;

contacting the dielectric thin film with a blocking reactant such that the blocking reactant adsorbs in a self-limiting manner on the surface of the dielectric thin film;

removing excess blocking reactant from the reaction space;

contacting the dielectric thin film with a dopant precursor comprising Hf such that the dopant precursor adsorbs in a self limiting manner on the surface of the dielectric thin film; and

removing excess dopant precursor,

wherein the blocking reactant and dopant precursor are selected such that a desired concentration of Hf is deposited on the dielectric thin film.

20. The method of claim 19, wherein the dielectric thin film is contacted simultaneously with the dopant precursor and the blocking reactant.

21. The method of claim 19, wherein the dielectric thin film is contacted sequentially with the blocking reactant and the dopant precursor.

22. The method of claim 19, wherein the lower interface film comprises SiON.

23. The method of claim 19, wherein the dopant precursor comprises HfCl₄.

24. The method of claim 19, wherein the blocking reactant comprises tri-methyl-aluminum (TMA).

25. The method of claim 19, wherein the blocking reactant comprises Si.

26. The method of claim 25, wherein the blocking reactant comprises a silicon halide compound.

27. The method of claim 26, wherein the silicon halide compound is selected from the group consisting of SiF₄, SiCl₄, SiBr₄, and SiI₄.

28. The method of claim 19, further comprising contacting the dielectric thin film with a third reactant that reacts with the dopant precursor to form Hf.

29. The method of claim 19, wherein the third reactant is selected from the group consisting of H₂O, O₃, O radical, H₂O₂ and D₂O.

30. The method of claim 19, wherein the gate electrode comprises poly-silicon.

31. The method of claim 19, wherein the concentration of Hf after contacting the lower interface film with the third reactant is about 1×

10¹⁴ atoms/cm².