Interface control for film deposition by gas-cluster ion-beam processing

{
  "publication_number": "US6498107B1",
  "country": "US",
  "kind": "B1",
  "title": "Interface control for film deposition by gas-cluster ion-beam processing",
  "abstract": "Methods are disclosed for gas-cluster ion-beam deposition of thin films on silicon wafers rendered free of native oxides by termination of the surface bonds and subsequent reactive deposition. Hydrogen termination of the surface of silicon renders it inert to reoxidation from oxygen-containing environmental gasses, even those found as residue in vacuum systems, such as those used to deposit films. Nitrogen termination improves the interface with overlying metal-oxide thin films. The film is formed in intimate contact with the silicon crystal surface forming a nearly ideal interface.",
  "claims": [
    "1. A method for film deposition on a semiconductor, comprising the steps of: removing oxide from a surface of die semiconductor; terminating the surface of the semiconductor with hydrogen; placing the semiconductor in a vacuum environment; desorbing volatile materials from the surface of the semiconductor by heating the semiconductor to a temperature of between approximately 200 and 400° C.; subsequently bombarding the surface of the semiconductor with gas-cluster ions in order to remove said hydrogen; and forming a film on the surface of the semiconductor.",
    "2. The method of claim 1, wherein said oxide is in the form of an oxide film.",
    "3. The method of claim 2, wherein said oxide film is a native oxide film.",
    "4. The method of claim 1, wherein said removing step is performed with an HF solution.",
    "5. The method of claim 1, wherein said hydrogen termination step is performed with an HF solution.",
    "6. The method of claim 1, wherein the semiconductor comprises a silicon wafer.",
    "7. The method of claim 1, wherein the gas-cluster ions are reactive.",
    "8. The method of claim 1, wherein the film formed on the surface of the semiconductor comprises a dielectric film.",
    "9. The method of claim 1, further comprising the step of depositing a metal film on said film on the surface of the semiconductor to form an MIS capacitor.",
    "10. A method for film deposition on a semiconductor, comprising the steps of: placing the semiconductor in a vacuum environment; desorbing volatile materials from a surface of the semiconductor by heating the semiconductor to a temperature of between approximately 200 and 400° C.; subsequently removing oxide from the surface of the semiconductor by bombarding said oxide with gas-cluster ions; terminating the surface of the semiconductor; and forming a film on the surface of the semiconductor.",
    "11. The method of claim 10, wherein said gas-cluster ions are inert.",
    "12. The method of claim 11, wherein said inert gas-cluster ions comprise argon gas-cluster ions.",
    "13. The method of claim 10, wherein the semiconductor comprises a silicon wafer.",
    "14. The method of claim 10, wherein said terminating step is performed by bombarding the surface of the semiconductor with gas-cluster ions.",
    "15. The method of claim 14, wherein said gas-cluster ions comprise nitrogen gas-cluster ions.",
    "16. The method of claim 10, wherein the step of forming said film on the surface of the semiconductor is performed by bombarding the surface of the semiconductor with gas-cluster ions.",
    "17. The method of claim 16, wherein said gas-cluster ions comprise nitrogen gas-cluster ions.",
    "18. The method of claim 11, wherein said terminating step is performed by bombarding the surface of the semiconductor with nitrogen gas-cluster ions.",
    "19. The method of claim 18, wherein the steps of removing the oxide and terminating the surface are repeated at least one additional time.",
    "20. The method of claim 10, further comprising the step of depositing a metal film on said film on the surface of the semiconductor to form an MIS capacitor.",
    "21. The method of claim 19, further comprising the step of depositing a metal film on said film on the surface of the semiconductor to form an MIS capacitor.",
    "22. The method of claim 10, wherein the film formed on the surface of the semiconductor comprises a dielectric film.",
    "23. A method for film deposition on a semiconductor, comprising the steps of: placing the semiconductor in a vacuum environment; desorbing volatile materials from a surface of the semiconductor by heating the semiconductor to a temperature of between approximately 200 and 400° C.; subsequently removing oxide from the surface of the semiconductor by bombarding said oxide with gas-cluster ions; and forming a film on the surface of the semiconductor.",
    "24. The method of claim 23, wherein said gas-cluster ions are inert.",
    "25. The method of claim 23, wherein the semiconductor comprises a silicon wafer.",
    "26. The method of claim 23, wherein the step of forming said film on the surface of the semiconductor is performed by bombarding the surface of the semiconductor with gas-cluster ions while substantially simultaneously depositing a material.",
    "27. The method of claim 26, wherein said material is selected from a group consisting of the elements Zr, Hf, Mg, Ti, and Y.",
    "28. The method of claim 26, wherein said gas-cluster ions are reactive.",
    "29. The method of claim 26, wherein said material is a vaporized metal.",
    "30. The method of claim 23, further comprising the step of depositing a metal film on said film on the surface of the semiconductor to form an MIS capacitor.",
    "31. The method of claim 23, wherein the film formed on the surface of the semiconductor comprises a dielectric film."
  ],
  "description_excerpt": "This invention relates generally to the formation of thin films, and, more particularly to the formation of thin dielectric films by gas-cluster ion-beam (GCIB) on surfaces rendered free of native oxides to assure high quality interfacial layers and films.\n\nThe use of a GCIB for etching, cleaning, and smoothing of the surfaces of various materials is known in the art (See for example, U.S. Pat. No. 5,814,194, Deguchi, et al., “Substrate Surface Treatment Method”, 1998). Means for creation of and acceleration of such GCIBs are also described in the Deguchi reference. It is also known (U.S. Pat. No. 5,459,326, Yamada, “Method for Surface Treatment with Extra-Low-Speed Ion Beam”, 1995) that atoms in a cluster ion are not individually energetic enough (on the order of a few electron volts) to significantly penetrate a surface to cause the residual sub-surface damage typically associated with the other types of ion beam processing in which individual ions may have energies on the order of thousands of electron volts. Nevertheless, the cluster ions themselves can be made sufficiently energetic (some thousands of electron volts), to effectively etch, smooth or clean surfaces as shown by Yamada & Matsuo (in “Cluster ion beam processing”, Matl. Science in Semiconductor Processing I, (1998) pp 27-41).\n\nThe heart of high-density memory and microprocessor chips is a very thin film of an electrically insulating material formed on the surface of a silicon crystal wafer.",
  "cpc": [
    "H10D 64/01342",
    "C23C 14/0031",
    "C23C 14/022",
    "H01J 2237/0812",
    "H10D 1/68",
    "H10D 64/01344",
    "H10D 64/01346",
    "H10D 64/685",
    "H10D 64/691",
    "H10D 64/693",
    "H10P 14/6316",
    "H10P 14/6328",
    "H10P 14/6502",
    "H10P 14/6508",
    "H10P 14/6938",
    "H10P 14/69392",
    "H10P 14/69433",
    "H10P 50/283",
    "H10P 70/18",
    "H10P 70/23"
  ],
  "ipc": [
    "C23C 14/00",
    "C23C 14/02",
    "H01L 29/51",
    "H10B 12/00",
    "H10B 20/00",
    "H10P 14/69",
    "H10P 14/692",
    "H10P 14/694"
  ],
  "assignees": [
    "TEL Epion Inc"
  ],
  "inventors": [
    "David B. Fenner"
  ],
  "filing_date": "2000-05-01",
  "publication_date": "2002-12-24",
  "grant_date": "2002-12-24",
  "priority_date": "2000-05-01",
  "application_number": "US-56303500-A",
  "family_id": "24248835",
  "cited_by_count": 53,
  "citations": [
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}