Arrangement and method for measurement of the temperature and of the thickness growth of silicon rods in a silicon deposition reactor

{
  "publication_number": "US2012027916A1",
  "country": "US",
  "kind": "A1",
  "title": "Arrangement and method for measurement of the temperature and of the thickness growth of silicon rods in a silicon deposition reactor",
  "abstract": "An arrangement for measurement of temperature and thickness growth of silicon rods in a silicon deposition reactor employs a temperature measurement device located outside the reactor. Continuous temperature measurement and measurement of the thickness growth throughout the entire deposition process is achieved with a contactlessly operating temperature measurement device arranged outside the silicon deposition reactor in front of a viewing window. The temperature measurement device can be pivoted horizontally about a rotation axis by a rotating drive. The pivoting axis runs parallel to a longitudinal axis of the silicon rod, and the central axis of the temperature measurement device runs through the pivoting axis.",
  "claims": [
    "1. Arrangement for measurement of temperature and thickness growth of silicon rods in a silicon deposition reactor through a viewing window, comprising: a contactlessly operating temperature measurement device for the temperature measurement arranged outside the silicon deposition reactor in front of the viewing window, and a rotating device for pivoting the temperature measurement device horizontally about a pivoting axis, wherein the pivoting axis runs parallel to a longitudinal axis of the silicon rod, and wherein a central axis of the temperature measurement device runs through the pivoting axis. 2. Arrangement according to claim 1, wherein the pivoting axis is arranged outside a wall of the silicon deposition reactor, in front of the viewing window. 3. Arrangement according to claim 1, wherein the pivoting axis is arranged within the silicon deposition reactor, behind the viewing window. 4. Arrangement according to claim 1, wherein the viewing window is cooled. 5. Arrangement according to claim 4, wherein the viewing window is provided with liquid cooling. 6. Arrangement according to claim 1, wherein a rotatable polarization filter is arranged between the temperature measurement device and the viewing window. 7. Arrangement according to claim 1, wherein the temperature measurement device comprises a pyrometer. 8. Arrangement according to claim 7, further comprising a memory for storing measurement data of the pyrometer and a monitor for displaying the measurement data. 9. Arrangement according to claim 8, wherein a grid is superimposed on the data displayed on the monitor. 10. Arrangement according to claim 1, wherein the temperature measurement device comprises a thermal imaging camera. 11. Arrangement according to claim 10, wherein the thermal imaging camera is stationary. 12. Arrangement according to claim 1 wherein the temperature measurement device is coupled to the rotating drive to position the pivoting axis behind the viewing window, the rotating drive is located below the viewing window, and the viewing window is arranged in a tubular connecting stub located on a wall of the reactor. 13. The arrangement according to claim 1, in combination with the deposition reactor. 14. Method for measurement of temperature and thickness growth of thin silicon rods in a silicon deposition reactor, comprising: arranging the thin silicon rods in the silicon deposition reactor, removal of oxygen from the reactor and starting of a deposition process by integration of the thin silicon rods in an electrical circuit, and introducing tricholorosilane into the reactor to coat the rods, scanning of the thin silicon rods by a temperature measurement device located outside the silicon deposition reactor, and selecting one coated rod of the thin silicon rods being coated and focusing of the temperature measurement device onto the one coated rod, recording a temperature curve plotted against time for the one coated rod and simultaneously measuring the thickness growth of the one coated rod by horizontally pivoting the temperature measurement device until a sudden light/dark change is identified and pivoting the temperature measurement device in an opposite pivoting direction until a further sudden light/dark change is identified, calculating diameter of the one coated rod from pivoting angle and distance between the pivoting axis and the silicon rod, and repeating the measurement of the thickness growth at predetermined intervals, and ending the deposition process after the one coated rod has reached a predetermined thickness. 15. Method according to claim 14, wherein the intervals are ≧zero. 16. Method according to claim 14, wherein a plurality of thin silicon rods are selected and measured, staggered in time. 17. Method according to claim 14, wherein reflections on an inner wall of the silicon deposition reactor before start of the scanning masked out by a polarization filter."
  ],
  "description_excerpt": "The invention relates to an arrangement and a method for measurement of the temperature and of the thickness growth of silicon rods in a silicon deposition reactor by means of a temperature measurement device which is located outside the reactor.\n\nThe manufacturing process for polycrystalline silicon is based on a method in which gaseous trichlorosilane is passed together with hydrogen into a vacuum reactor in which thin silicon rods have previously been arranged as the raw material, and are electrically heated to temperatures of around 1100 degrees Celsius. This method has become known as the so-called SIEMENS method. In this case, strict attention must be paid to not reaching the melting temperature of silicon. In this case, silicon is deposited on the silicon rods, with the silicon being created in a chemical reaction from the trichlorosilane. The pillars of polysilicon which are created in this way are then available for further processing.\n\nThe pillars are once again broken down into relatively small chunks for the photovoltaic industry, and are then melted in quartz crucibles and, if required, are reshaped into monocrystalline or polycrystalline blocks, from which the blanks for solar modules are then manufactured.",
  "cpc": [
    "G01B 11/0683",
    "C01B 33/035",
    "C23C 16/24",
    "C23C 16/4418",
    "C23C 16/52"
  ],
  "ipc": [
    "C23C 16/52"
  ],
  "assignees": [
    "Centrotherm Sitec GmbH"
  ],
  "inventors": [
    "Vollmar Wilfried",
    "Frank Stubhan"
  ],
  "filing_date": "2010-01-28",
  "publication_date": "2012-02-02",
  "priority_date": "2009-01-29",
  "application_number": "US-201013145933-A",
  "family_id": "42317574",
  "cited_by_count": 3,
  "citations": [
    "US2981605A",
    "AT222184B",
    "US3737130A",
    "US3791887A",
    "US4125643A",
    "GB2159272A",
    "US4919899A",
    "US20100124248A1"
  ]
}