UDK 004.07 Doi: 10.31772/2587-6066-2018-19-3-550-561
INCREASING THE ACCURACY OF THE CONTACT METHOD OF MEASURING THE CURRENT SQUARE OF CRYSTALS GROWN BY THE WAY OF THE CZOHRALSKY
S. P. Sahansky*, S. E. Yulenkov
Reshetnev Siberian State University of Science and Technology, 31, Krasnoyarsky Rabochy Av., Krasnoyarsk, 660037, Russian Federation. *E-mail: Sahanskiy@yandex.ru
For crystals grown from a liquid melt by the Czochralski method, when monitoring and controlling the current crystal area, based on the contact method of measurement, the basic requirements for ensuring the accuracy of measuring the area of the crystal on the cylindrical part of the growing are determined. In the control system with respect to the coordinates of the movement of the crystal and the crucible, it is necessary to use photo-reading optical rulers, with a sampling resolution of 0.1 μm, to determine the amount of movement during the control signal evaluation cycle. To eliminate the error due to the accuracy of stabilization of the melt level in the crucible, the following algorithm for the operation of the crystal growing apparatus is proposed. During the evaluation of the control signal on the cylindrical part of the growing crystal, the sampling time of the predetermined number of pulses of the crucible movement is adopted. Calculation of the evaluation time of the control signal begins at the moment of closure of the melt sensor and ends when the melt sensor closes, provided that a predetermined number of pulses of the crucible transfer is sampled. The evaluation time of the control signal in the previous control cycle is used in the current cycle to calculate the closure pause as part of the calculated evaluation cycle time. In the control system, at the moment of closing the contact sensor, a pause of the closed sensor is maintained, followed by a similar pause of the open state of the level sensor. During the moments of pauses, the state of the contact sensor by the control system is not analyzed and the control of the crucible lift occurs with a slowed and accelerated rate of the crucible lift during the moments of the “conditionally” closed and “conditionally” open states of the level sensor. All this ensures in this control system the accuracy of measuring the current area of the crystal, on the cylindrical part, by a value not worse than 1 %.
Keywords: growing, crystals, contact method of measurement.
References

1. Schmidt F., Voszka R. Phantom controlled automatic Czochralski growth appparatuss. Crystal Research and Technology. 1981, Vol. 10, No. 11, P. 127–128.

2. Pat. 2337169. Federal Republic of Germany, ICI В01 J17/18-1974.

3. Sahansky S. P., Podkopaev O. I., Petrik V. F. Sposob upravleniya protsessom vyrashchivaniya monokristallov germaniya iz rasplava i ustroystvo dlya ego osushchestvleniya [A method for controlling the process of growing single crystals of germanium from the melt, and a device for its implementation]. Patent RF, no. 2128250, 1997.

4. Sahansky S. P., Podkopaev O. I., Petrik V. F., Laptenok V. D. Sposob upravleniya protsessom vyrashchivaniya monokristallov germaniya iz rasplava i ustroystvo dlya ego osushchestvleniya [A method for controlling the process of growing single crystals of germanium from the melt, and a device for its implementation]. Patent RF, no. 2184803, 1999.

5. Sakhanskiy S. P. [Controlling the shape of semiconductor crystals when grown according to the Czochralski method]. J/Sib. Fed. Univ. Eng., Technol. 2014, Vol. 7, No. 1, P. 20–31 (In Russ.).

6. Sakhanskiy S. P. [Method for controlling the growth of germanium single crystals from a melt]. Perspektivnye materialy, tekhnologii, konstruktsii i ekonomika : sb. nauchn. tr.; pod. red. V. V. Statsury GATsMiZ [Perspective Materials, Technologies, Constructions and Economics: Sat. scientific. tr.; under. Ed. V. V. Statsura; GATSMiZ]. 2000, Iss. 6, P. 391–393. (In Russ.).

7. Sakhanskiy S. P. [Estimation of the accuracy of control based on the “improved contact method” for controlling the germanium germanium growth from a melt by the Czochralski method]. Mat. 4 Vseros. nauchn. konf. “Reshetnevskie chteniya” (11–14 noyabrya 2002 g, Krasnoyarsk) [Math. 4 Vseros. scientific. Conf “Reshetnev’s readings” (November 11–14, 2002, Krasnoyarsk). Krasnoyarsk, 2002, p. 68–71 (In Russ.).

8. Sakhanskiy S. P. [Features of designing melt level position sensors for germanium] Perspektivnye materialy, tekhnologii, konstruktsii, ekonomika. Sb. nauchn. tr., pod obshch. red. V. V. Statsury; GATsMiZ [Perspective materials, technologies, constructions, economy. Coll. scientific. Ed. V. V. Statsura, GATSMiZ. 2005, Iss. 11, P. 169–170.

9. Sakhanskiy S. P. [The combination of a control system for growing germanium single crystals on the basis of a contact method for measuring the diameter and simultaneous drawing of a single crystal from a spinneret by the Stepanov method]. Vestnik SibGAU. 2005, No. 6, P. 246–247 (In Russ.).

10. Sakhanskiy S. P. [Basic mathematical relationships of the contact method for controlling the growth of single crystals by the Czochralski method]. Vestnik SibGAU. 2005, No. 7, P. 85–88 (In Russ.).

11. Sakhanskiy S. P. [Determination of the correction value of the control signal by diameter, from the change in the height of the column of the meniscus of the crystal, with the contact method for controlling the growth of single crystals by the Czochralski method]. Vestnik SibGAU. 2005, No. 7, P. 89–90 (In Russ.).

12. Sakhanskiy S. P. [Determination of the magnitude of the melt fluctuation and sensitivity with a contact method for controlling the growth of single crystals by the Czochralski method]. Vestnik SibGAU. 2006, No. 1 (8), P. 103–104 (In Russ.).

13. Sakhanskiy S. P. [The error in the contact method for measuring the current area of the grown germanium single crystal]. Pribory i sistemy. Upravlenie. Kontrol’. Diagnostika. 2009, No. 2, P. 43–46 (In Russ.).

14. Sakhanskiy S. P. [Measurement of the area of a single crystal in the system for automatic control of germanium germination.]. Mekhatronika. Avtomatizatsiya. Upravlenie. 2008, No. 8, P. 44–48 (In Russ.).

15. Sakhanskiy S. P. [Plant for growing germanium single crystals on the basis of the contact method of measurement]. Bulletin of the Samara State University. acad. S. P. Korolev. 2008, Iss. 2, P. 100–105 (In Russ.).

16. Sakhanskiy S. P. [Measurement and control of the crystal area on a germanium stretch unit]. Vestnik SibGAU. 2008, Vol. 1, No. 18, P. 148–150 (In Russ.).

17. Sakhanskiy S. P. Upravlenie protsessom vyrashchivaniya monokristallov germaniya: monografiya [Management process of growing single crystals of germanium: monograph]. Krasnoyarsk, SibGAU Publ., 2008, 104 p.

18. Sakhanskiy S. P. [Measurement of the area of crystals grown from a liquid melt by the Czochralski method, based on the control of the conditions for closing the contact melt level sensor]. J/Sib. Fed. Univ. Eng., Technol. 2015, Vol. 7, No. 8, P. 835–850.


Sakhanskiy Sergei Pavlovich – Dr. Sc., professor, Department of Information and control system, Reshetnev Siberian State University of Science and Technology. E-mail: Sahanskiy@yandex.ru.

Yulenkov Svyatoslav Evgenievich – postgraduate student, specialist in teaching and methodical work, Reshetnev Siberian State University of Science and Technology. E-mail: yulenkov_se@sibsau.ru.


  INCREASING THE ACCURACY OF THE CONTACT METHOD OF MEASURING THE CURRENT SQUARE OF CRYSTALS GROWN BY THE WAY OF THE CZOHRALSKY