Chemical vapor deposition technique for depositing titanium silicide on semiconductor wafers

• US 5,278,100 A
• Filed: 11/08/1991
• Issued: 01/11/1994
• Est. Priority Date: 11/08/1991
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Sandhu, Gurtej S., Doan, Trung T.
• Primary Examiner(s): Maples, John S.
• Application Number:
  US07/789,585
• Time in Patent Office: 795 Days
• Field of Search: 148/DIG. 147, 437/200, 437/245
• US Class Current: 438/681
• CPC Class Codes: H01L 21/285 from a gas or vapour, e.g. condensation
• CPC Class Codes: H01L 21/28518 the conductive layers comprising silicides H01L21/28537 takes precedence
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76855 After-treatment introducing at least one additional element into the layer
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: Y10S 148/147 Silicides

Abstract

A method of providing a conformal layer of TiSi_x atop a semiconductor wafer within a chemical vapor deposition reactor includes the following steps: a) positioning a wafer within the reactor; b) injecting selected quantities of gaseous Ti(NR₂)₄ precursor, gaseous silane and a carrier gas to within the reactor, where R is selected from the group consisting of H and a carbon containing radical, the quantities of Ti(NR₂)₄ precursor and silane being provided in a volumetric ratio of Ti(NR₂)₄ to silane of from 1:300 to 1:10, the quantity of carrier gas being from about 50 sccm to about 2000 sccm and comprising at least one noble gas; and c) maintaining the reactor at a selected pressure and a selected temperature which are effective for reacting the precursor and silane to deposit a film on the wafer, the film comprising a mixture of TiSi_x and TiN, the selected temperature being from about 100° C. to about 500° C., and the selected pressure being from about 150 mTorr to about 100 Torr.

Claims

1. A chemical vapor deposition method of providing a conformal layer of TiSi_x atop a semiconductor wafer within a chemical vapor deposition reactor, the method comprising the following steps:

positioning a wafer within the reactor;

injecting a gaseous titanium organometallic precursor, gaseous silane and a carrier gas within the reactor; and

maintaining the reactor at a pressure and a temperature which are effective for reacting the precursor and silane to deposit a film on the wafer, the film comprising TiSi_x.

2. The chemical vapor deposition method of claim 1 wherein the gases are injected to provide a volumetric ratio of titanium organometallic precursor to silane of from 1:

300 to 1;

10.

3. The chemical vapor deposition method of claim 2 wherein the gases are injected to provide a volumetric ratio of titanium organometallic precursor to silane of about 1:

80.

4. The chemical vapor deposition method of claim 1 wherein the temperature is from about 100°

C. to about 500°

C., and the pressure is from about 150 mTorr to about 100 Torr.

5. The chemical vapor deposition method of claim 4 wherein the temperature is about 400°

C., and the pressure is about 400 mTorr.

6. The chemical vapor deposition method of claim 1 wherein the carrier gas comprises at least one noble gas, the carrier gas being injected at a rate of from about 50 sccm to about 2000 sccm.

7. The chemical vapor deposition method of claim 1 wherein,

the gases are injected to provide a volumetric ratio of titanium organometallic precursor to silane of from 1:

300 to 1;

10, and the carrier gas is provided at a flow rate of from about 50 sccm to about 2000 sccm; and

the temperature is from about 100°

C. to about 500°

C., and the pressure is from about 150 mTorr to about 100 Torr.

8. The chemical vapor deposition method of claim 1 wherein gases within the reactor are reacted to deposit a film on the wafer comprising a mixture of TiSi_x and TiN.

9. The chemical vapor deposition method of claim 1 further comprising annealing the deposited TiSi_x film to incorporate silicon from the wafer thereby reducing contact resistance.

10. The chemical vapor deposition method of claim 9 wherein the annealing is conducted in an atmosphere containing predominately N₂ or NH₃.

11. The chemical vapor deposition method of claim 1 wherein the titanium organometallic precursor consists essentially of Ti(NR₂)₄, where R is selected from the group consisting of H and a carbon containing radical.

12. The chemical vapor deposition method of claim 11 wherein the gases are injected to provide a volumetric ratio of titanium organometallic precursor to silane of from 1:

300 to 1;

10.

13. The chemical vapor deposition method of claim 11 wherein the temperature is about 400°

C., and the pressure is about 400 mTorr.

14. The chemical vapor deposition method of claim 11 wherein the gases are injected to provide a volumetric ratio of titanium organometallic precursor to silane of from 1:

300 to 1;

10, and the temperature is about 400°

C. and the pressure is about 400 mTorr.

15. The chemical vapor deposition method of claim 11 wherein the carrier gas comprises at least one noble gas, the carrier gas being injected at a rate of from about 50 sccm to about 2000 sccm.

16. The chemical vapor deposition method of claim 11 wherein the titanium organometallic precursor consists essentially of Ti(N(C₂ H₅)₂)₄.

17. The chemical vapor deposition method of claim 11 further comprising annealing the deposited TiSi_x film to incorporate silicon from the wafer thereby reducing contact resistance.

18. The chemical vapor deposition method of claim 1 wherein the titanium organometallic precursor consists essentially of Ti(N(CH₃)₂)₄.

19. The chemical vapor deposition method of claim 18 wherein the gases are injected to provide a volumetric ratio of titanium organometallic precursor to silane of from 1:

300 to 1;

10.

20. The chemical vapor deposition method of claim 18 wherein the temperature is about 400°

C., and the pressure is about 400 mTorr.

21. The chemical vapor deposition method of claim 18 wherein the gases are injected to provide a volumetric ratio of titanium organometallic precursor to silane of from 1:

300 to 1;

10, and the temperature is about 400°

C. and the pressure is about 400 mTorr.

22. The chemical vapor deposition method of claim 18 wherein the carrier gas comprises at least one noble gas, the carrier gas being injected at a rate of from about 50 sccm to about 2000 sccm.

23. The chemical vapor deposition method of claim 18 further comprising annealing the deposited TiSi_x film to incorporate silicon from the wafer thereby reducing contact resistance.

24. A chemical vapor deposition method of providing a conformal layer of TiSi_x atop a semiconductor wafer within a chemical vapor deposition reactor, the method comprising the following steps:

positioning a wafer within the reactor;

injecting selected quantities of gaseous Ti(NR₂)₄ precursor, gaseous silane and a carrier gas to within the reactor, where R is selected from the group consisting of H and a carbon containing radical, the quantities of Ti(NR₂)₄ precursor and silane being provided in a volumetric ratio of Ti(NR₂)₄ to silane of from 1;

300 to 1;

10, the quantity of carrier gas being from about 50 sccm to about 2000 sccm and comprising at least one noble gas; and

maintaining the reactor at a selected pressure and a selected temperature which are effective for reacting the precursor and silane to deposit a film on the wafer, the film comprising a mixture of TiSi_x and TiN, the selected temperature being from about 100°

C. to about 500°

C., and the selected pressure being from about 150 mTorr to about 100 Torr.

25. The chemical vapor deposition method of claim 24 wherein the quantities of gases are selected to provide a volumetric ratio of Ti(NR₂)₄ precursor to silane of about 1:

80, and the quantity of carrier gas is from about 50 sccm to about 2000 sccm.

26. The chemical vapor deposition method of claim 24 further comprising annealing the deposited TiSi_x film to incorporate silicon from the wafer thereby reducing contact resistance.

27. The chemical vapor deposition method of claim 24 wherein the Ti(NR₂)₄ precursor consists essentially of Ti(N(CH₃)₂)₄.

28. The chemical vapor deposition method of claim 27 wherein the quantities of gases are selected to provide a volumetric ratio of Ti(NR₂)₄ precursor to silane of about 1:

80, and the quantity of carrier gas is from about 50 sccm to about 2000 sccm.