Chemical vapor deposition of titanium from titanium tetrachloride and hydrocarbon reactants
View Patent ↗A new process for depositing titanium metal layers via chemical vapor deposition is disclosed. The process provides deposited titanium layers having a high degree of conformality, even in trenches and contact openings having aspect ratios greater than 1:5.
1. A plasma enhanced chemical vapor deposition process comprising:
admitting a hydrocarbon gas into a deposition chamber;
admitting titanium tetrachloride gas into the deposition chamber;
forming a plasma in the deposition chamber having at a power level greater than a first ionization energy, but less than a second ionization energy, of the hydrocarbon gas for forming hydrocarbon radicals therein; and
heating a substrate to a temperature for some of the hydrocarbon radicals formed from the hydrocarbon gas to react with some of the chlorine atoms from the titanium tetrachloride gas for depositing titanium metal on a portion of a surface of the substrate.
2. The process of claim 1 , wherein the substrate is heated to a temperature within a range of about 200° C. to about 500° C.
3. The process of claim 1 , wherein the hydrocarbon gas is selected from a group of compounds comprising C n H 2n+2 , C n H 2n and C n H 2n−2 .
4. The process of claim 1 , wherein the hydrocarbon gas comprises an alkane having fewer than five carbon atoms per molecule.
5. The process of claim 4 , wherein the hydrocarbon gas includes methane.
6. The process of claim 1 , further comprising:
mounting the substrate on a susceptor;
heating the susceptor; and
heating the substrate using the susceptor.
7. The process of claim 1 , wherein the titanium tetrachloride gas includes a titanium tetrachloride gas mixed with a carrier gas selected from a group consisting of helium, argon and hydrogen.
8. The process of claim 7 , wherein the titanium tetrachloride gas includes titanium tetrachloride gas introduced into the carrier gas using a bubbler apparatus.
9. The process of claim 7 , wherein a liquid injector sprays the titanium tetrachloride and passes through a vaporizer.
10. The process of claim 1 , wherein the hydrocarbon gas includes a hydrocarbon gas mixed with a carrier gas selected from a group consisting of helium and argon.
11. The process of claim 1 , further comprising:
removing reaction products from the deposition chamber during the process.
12. The process of claim 11 , wherein an alkyl chloride gas comprises a reaction product.
13. The process of claim 1 , wherein the deposition chamber comprises a cold wall deposition chamber, with walls thereof maintained at a temperature within a preferred range of about 100° C. to about 200° C. for preventing condensation of the titanium tetrachloride gas thereon.
14. The process of claim 1 , wherein the deposition chamber comprises a hot wall deposition chamber.
15. The process of claim 1 , wherein the plasma comprises a plasma produced with a radio frequency source.
16. The process of claim 15 , wherein the radio frequency source comprises a radio frequency source having a power setting within a range of about 20 watts to about 100 watts.
17. The process of claim 15 , wherein the radio frequency source comprises a radio frequency source having a frequency greater than about 10 KHz.
18. The process of claim 1 , wherein the deposition chamber comprises a deposition chamber for maintaining a pressure within a range of about 2 torr to about 100 torr.
19. The process of claim 1 , wherein the deposition chamber comprises a deposition chamber for maintaining a pressure within a preferred range of about 2 torr to about 5 torr.
20. The process of claim 1 , further comprising:
premixing the titanium tetrachloride gas and the hydrocarbon gas before being admitted to the deposition chamber.
21. The process of claim 20 , wherein a ratio of the hydrocarbon gas to the titanium tetrachloride gas comprising the premixture thereof comprises a ratio of between about four and about one thousand to one.
22. The process of claim 1 , wherein the substrate comprises a semiconductor wafer.
23. A plasma enhanced chemical vapor deposition process comprising:
admitting hydrocarbon gas into a deposition chamber;
admitting titanium tetrachloride gas into the deposition chamber;
forming a plasma within the deposition chamber of the hydrocarbon gas for forming hydrocarbon radicals;
maintaining the plasma at a power level greater than a first ionization energy, but less than a second ionization energy, of the hydrocarbon gas for forming the hydrocarbon radicals; and
heating a semiconductor wafer to a temperature sufficient to induce some of the hydrocarbon radicals to react with some chlorine atoms from the titanium tetrachloride gas for forming chlorinated hydrocarbon molecules for depositing titanium metal on a portion of a surface of the semiconductor wafer.
24. The process of claim 23 , further comprising:
maintaining the deposition chamber at a pressure within a range of about 2 torr to about 10 torr.
25. The process of claim 23 , wherein the power level comprises a radio frequency source operating at a power setting within a range of about 20 watts to about 100 watts and at a frequency greater than about 10 KHz.
26. The process of claim 23 , further comprising:
premixing the titanium tetrachloride gas and the hydrocarbon gas for their admission to the deposition chamber in a ratio of hydrocarbon gas to the titanium tetrachloride gas being between about four and about one thousand to one.
27. The process of claim 23 , wherein the hydrocarbon gas includes methane.
28. The process of claim 23 , wherein the hydrocarbon gas includes a hydrocarbon gas selected from a group consisting of compounds C n H 2n+2 , C n H 2n and C n H 2n−2 .
29. A plasma enhanced chemical vapor deposition process comprising:
flowing a hydrocarbon gas into a deposition chamber;
flowing a titanium tetrachioride gas into the deposition chamber;
forming a plasma in the deposition chamber using a power level substantially in a range of greater than a first ionization energy of the hydrocarbon gas to less than a second ionization energy of the hydrocarbon gas for forming hydrocarbon radicals in the hydrocarbon gas; and
heating a substrate to a temperature for some of the hydrocarbon radicals formed from the hydrocarbon gas to react with some chlorine atoms from the titanium tetrachioride gas for depositing titanium metal on a portion of a surface of the substrate.
30. The process of claim 29 , wherein the substrate is heated to a temperature within a range of about 200° C. to about 500° C.
31. The process of claim 29 , wherein the hydrocarbon gas is selected from a group of compounds comprising C n H 2n+2, C n H 2n and C n H 2n−2 .
32. The process of claim 29 , wherein the hydrocarbon gas comprises an alkane having fewer than five carbon atoms per molecule.
33. The process of claim 32 , wherein the hydrocarbon gas includes methane.
34. The process of claim 29 , further comprising:
mounting the substrate on a susceptor;
heating the susceptor; and
heating the substrate using the susceptor.
35. The process of claim 29 , wherein the titanium tetrachioride gas includes a titanium tetrachioride gas mixed with a carrier gas selected from a group consisting of helium, argon and hydrogen.
36. The process of claim 35 , wherein the titanium tetrachioride gas includes titanium tetrachioride gas introduced into the carrier gas using a bubbler apparatus.
37. The process of claim 36 , wherein a liquid injector sprays the titanium tetrachloride gas and passes through a vaporizer.
38. The process of claim 29 , wherein the hydrocarbon gas includes a hydrocarbon gas mixed with a carrier gas selected from a group consisting of helium and argon.
39. The process of claim 29 , further comprising:
removing reaction products from the deposition chamber during the process.
40. The process of claim 39 , wherein an alkyl chloride gas comprises a reaction product.
41. The process of claim 29 , wherein the deposition chamber comprises a cold wall deposition chamber, the walls thereof maintained at a temperature within a preferred range of about 100° C. to about 200° C. for preventing condensation of titanium tetrachioride thereon.
42. The process of claim 29 , wherein the deposition chamber comprises a hot wall deposition chamber.
43. The process of claim 29 , wherein the plasma comprises plasma produced by a radio frequency source.
44. The process of claim 43 , wherein the radio frequency source comprises a radio frequency source having a power setting within a range of about 20 watts to about 100 watts.
45. The process of claim 43 , wherein the radio frequency source comprises a radio frequency source having a frequency greater than about 10 KHz.
46. The process of claim 29 , wherein the deposition chamber comprises a deposition chamber for maintaining a pressure within a range of about 2 torr to about 100 torr.
47. The process of claim 29 , wherein the deposition chamber comprises a deposition chamber for maintaining a pressure within a preferred range of about 2 torr to about 5 torr.
48. The process of claim 29 , further comprising:
premixing the titanium tetrachioride gas and the hydrocarbon gas before flowing into the deposition chamber.
49. The process of claim 48 , wherein a ratio of the hydrocarbon gas to the titanium tetrachioride gas comprising the premixture thereof comprises a ratio of between about four and about one thousand to one.
50. The process of claim 29 , wherein the substrate comprises a semiconductor wafer.
51. A deposition process having a hydrocarbon gas and a titanium tetrachioride gas in a chamber comprising:
providing a plasma for the chamber having a power level greater than a first ionization energy and less than a second ionization energy of the hydrocarbon gas for forming hydrocarbon radicals; and
heating a substrate to a temperature for some of the hydrocarbon radicals formed from the hydrocarbon gas to react with some chlorine atoms from the titanium tetrachloride gas for depositing titanium metal on a portion of a surface of the substrate.
52. The process of claim 51 , wherein the substrate is heated to a temperature within a range of about 200° C. to about 500° C.
53. The process of claim 51 , wherein the hydrocarbon gas is selected from a group of compounds comprising C n H 2n+2 , C n H 2n and C n H 2n−2 .
54. The process of claim 51 , wherein the hydrocarbon gas comprises an alkane having fewer than five carbon atoms per molecule.
55. The process of claim 54 , wherein the hydrocarbon gas includes methane.
56. The process of claim 51 , further comprising:
mounting the substrate on a susceptor;
heating the susceptor; and
heating the substrate using the susceptor.
57. The process of claim 51 , wherein the titanium tetrachioride gas includes a titanium tetrachioride gas mixed with a carrier gas selected from a group consisting of helium, argon and hydrogen.
58. The process of claim 57 , wherein the titanium tetrachioride gas includes titanium tetrachioride gas introduced into the carrier gas using a bubbler apparatus.
59. The process of claim 57 , wherein a liquid injector sprays the titanium tetrachloride gas and passes through a vaporizer.
60. The process of claim 51 , wherein the hydrocarbon gas includes a hydrocarbon gas mixed with a carrier gas selected from a group consisting of helium and argon.
61. The process of claim 51 , further comprising:
removing reaction products from the chamber during the process.
62. The process of claim 61 , wherein an alkyl chloride gas comprises a reaction product.
63. The process of claim 51 , wherein the chamber comprises a cold wall deposition chamber, with walls thereof maintained at a temperature within a preferred range of about 100° C. to about 200° C. for preventing condensation of the titanium tetrachioride gas thereon.
64. The process of claim 51 , wherein the chamber comprises a hot wall deposition chamber.
65. The process of claim 51 , wherein the plasma comprises a plasma produced with a radio frequency source.
66. The process of claim 65 , wherein the radio frequency source comprises a radio frequency source having a power setting within a range of about 20 watts to about 100 watts.
67. The process of claim 65 , wherein the radio frequency source comprises a radio frequency source having a frequency greater than about 10 KHz.
68. The process of claim 51 , wherein the chamber comprises a deposition chamber for maintaining a pressure within a range of about 2 torr to about 100 torr.
69. The process of claim 51 , wherein the chamber comprises a chamber for maintaining a pressure within a preferred range of about 2 torr to about 5 torr.
70. The process of claim 51 , further comprising:
premixing the titanium tetrachioride gas and the hydrocarbon gas before being admitted to the chamber.
71. The process of claim 70 , wherein a ratio of the hydrocarbon gas to the titanium tetrachloride gas comprising the premixture thereof comprises a ratio of between about four and about one thousand to one.
72. The process of claim 51 , wherein the substrate comprises a semiconductor wafer.