Technology and design in electronic equipment, 2023, no. 1-2, pp. 43-49.
DOI: 10.15222/TKEA2023.1-2.43
UDC 621.382
Improvement of inverse characteristics of silicon varicap by using low-temperature gettering
(in Ukrainian)
Litvinenko V. N.1, Shutov S.V.2

Ukraine, 1Kherson State Agrarian and Economic University; 2Kyiv, V. E. Lashkaryov Institute of Semiconductor Physics NAS of Ukraine.

Varicaps are widely used in radio electronics as a variable capacitance, the value of which is controlled by voltage. However, it should be noted that the cost of varicaps remains relatively high due to a low yield of suitable devices. This is caused by high levels of reverse currents and low breakdown voltages of varicaps, which is determined by the significant dependence of the reverse characteristics of varicaps on the density of structural defects and heavy metal impurities in their active regions.
This study aimed to discover the causes and mechanisms of degradation of the reverse characteristics of varicaps with an ohmic contact based on nickel during annealing of a nickel film during the formation of an ohmic contact. Another goal was to determine the possibility of using gettering operations to prevent degradation of the reverse characteristics of varicaps and increase the yield of suitable devices.
The conducted experimental studies have shown that the reason for the degradation of the reverse characteristics of varicaps during the formation of a nickel-based ohmic contact is that, during the annealing of the nickel film, the excess nickel atoms not involved in the formation of NiSi silicide penetrate into the region of the space charge of the p-n junction.
The authors consider in detail the proposed technology for manufacturing nickel-based varicap structures with an ohmic contact using gettering of excess nickel atoms by carrying out additional low-temperature annealing of varicap structures using a ready-made "intrinsic geter" the Si-NiSi interface.
It is shown that the developed technology for fabricating varicap structures using gettering makes it possible to clean the active regions of varicaps from nickel atoms, which ensures a significant decrease in the level of varicap reverse currents and an increase in the yield of suitable devices.

Keywords: nickel atoms, ohmic contact, gettering, varicap, structural defects, reverse current.

Received 25.12 2022
  1. Bolic M., Drndarevic V. Digital gamma-ray spectroscopy based on FPGA technology. Nuclear Instruments and Methods in Physics Research A, 2002, vol. 482, iss. 3, pp. 761766.
  2. Timoshenkov S. P., Boyko A. N., Gaev D. S., Kalmykov R. M. Integrated high-capacity varicap based on porous silicon. Izvestiy vuzov. Elektronika, 2017, vol. 22, no. 1, pp. 1519. (Rus)
  3. Vikulin I.M., Stafeev V.I. Fizika Poluprovodnikovykh priborov [Physics of Semiconductor Devices]. Moscow, Radio i Svyaz', 1990, 264 p. (Rus)
  4. Irha V.I. Fluctuation processes in varicaps. Proceedings of the O. S. Popov NAT, 2016, no. 1, pp. 1521. (Ukr)
  5. Savchenko M. P., Starovoitova O. V. Negative feedback circuit by noise for an autogenerator with varicaps. Vestnik Baltiiskogo federal'nogo universiteta im. I. Kanta. Ser.: Fiziko-matematicheskie i tekhnicheskie nauki, 2016, no. 2. pp. 6669. (Rus)
  6. Spiridonov A.B., Lytsoev S.V., Petruchuk I.Y. Development of MDP-varicap with charge transfer in the microwave range. Applied Physics, 2016, no. 3, p. 7580. (Rus)
  7. Kurnosov A. I., Yudin V. V. Tekhnologiya proizvodstva poluprovodnikovykh priborov i integral'nykh mikroskhem [Fabrication technology of semiconductor devices and integrated circuits]. Moscow, Vysshaya Shkola, 1986, 368 p. (Rus)
  8. Pout Dzh., Tu K., Meyyer Dzh., Rozenberg R. Tonkiye plenki. Vzaimnaya diffuziya i reaktsii [Thin films. Mutual diffusion and reactions] / Ed by Dzh. Pouta. Moskow, Mir, 1982, 576 p. (Rus)
  9. Litvinenko V. N., Bohach N. V. Defects and impurities in silicon and methods for their gettering. Visnyk of KhNTU, 2017, vol. 60, iss. 1, pp. 3242. (Rus)
  10. Ravi .V. Imperfections and Impurities in Semiconductor Silicon. John Wiley & Sons, New York, 1981, 379 p.
  11. Bakhadirkhanov M.K., Ismailov B.K. Hettering properties of clusters of nickel atoms in the silicon lattice. Devices, 2020. vol. 240, iss. 6, pp. 4448. (Rus)
  12. Vorobey R.Y., Gusev O.K., Tyavlovsky K.L., Shadurskaya L.I., Rusakevich D.A. Getterization of epitaxial structures with rare earth elements. 10th International Conference "Pryborostroenie-2017". Section 1. Measuring systems and devices, technical safety means. Minsk, 2017, pp. 7374. (Rus)
  13. Kharchenko V.A. The getters in silicon. Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering, 2018, vol. 21, iss. 1, p. 517. (Rus)
  14. Litvinenko V. M., Bohach M. V. Modeling of heterization processes of fast-diffusing impurities in Schottky diode technology. Visnyk of KhNTU, 2019, vol. 68, no. 1, pp. 2533. (Ukr)
  15. Litvinenko V.M. Fizyka ta tekhnolohiya napivprovidnykovykh diodiv [Physics and Technology of Semiconductor Diodes]. Kherson, Vyshemirsky V.S., 2018, 184 p. (Ukr)
  16. Litvinenko V.M. Investigation of the influence of seasonal factors on reverse currents of silicon varicaps. Visnyk of KhNTU, 2016, vol. 56, iss. 1, p. 3944. (Rus)
  17. Nemtsev G.Z. Pekarev A.I., Chistyakov Yu.D., Burmistrov A.N. Gettering of point defects in semiconductor device manufacturing. Foreign Electronic Technology, 1981, vol. 245, iss. 311, p. 363. (Rus)
  18. Pilipenko V. A., Gorushko V. A., Petlitskiy A. N. et al. Methods and mechanisms of gettering of silicon structures in the production of integrated circuits. Tekhnologiya i Konstruirovanie v Elektronnoi Apparature, 2013, no. 23, pp. 4357. (Rus).
  19. Labunov V.A., Baranov I.L., Bondarenko V.P., Dorofeev A.M. Modern methods of gettering in semiconductor electronics technology. Foreign electronic technology, 1983, no. 11(270), p. 366. (Rus)
  20. Verkhovsky E.I. Methods for gettering impurities in silicon. Reviews on Electronic Technology. Ser. 2. Semiconductor Devices, 1981, iss. 8 (838), . 148. (Rus)
  21. Bokhan Yu.I., Kamenkov V.S., Tolochko N.K. Dominant factors of laser gettering of silicon wafers. Semiconductors Physics and Technology, 2015. vol. 49, iss. 2, p. 278282. (Rus)
  22. Vikulin I.M., Litvinenko V.N., Shutov S.V. et al. Enhancing parameters of silicon varicaps using laser gettering. Tekhnologiya i Konstruirovanie v Elektronnoi Apparature, 2018, no. 2, p. 2932.
  23. Pilipenko V.A., Vecher D.V., Ponaryadov V.V. et al. Influence of laser gettering on the structural and electrical parameters of epitaxial silicon layers. Vestnik of BSU. Ser. 1, 2007, iss. 2, p. 3942. (Rus)
  24. Litvinenko V. N., Vikulin I.M., Gorbachev V.E. mprovement of the reverse characteristics of Schottky diodes using gettering. Tekhnologiya i Konstruirovanie v Elektronnoi Apparature, 2019, no. 12, p. 3439.
  25. Litvinenko V.M., Vikulin I.M. Influence of surface properties on reverse characteristics of semiconductor devices. Visnyk of KhNTU, 2018, vol. 64, no. 1, pp. 4656. (Ukr)
  26. Litvinenko V. N., aganov Ye. A., Vikulin I.M., Gorbachev V.E. Influence of gettering on aluminum ohmic contact formation. Tekhnologiya i Konstruirovanie v Elektronnoi Apparature, 2020, no. 12, p. 4550.
  27. Vorobyev Yu.V., Dobrovolskyi V.N., Strykha V.Y. Metody issledovaniya poluprovodnikov [Semiconductor research methods]. Kyiv, Vyshcha Shkola, 1988, 232 p. (Rus)
  28. Murarka S.P. Silicides for VLSI Applications. Academic Press, 1983, 200 p.
  29. Milnes A. G. Deep Impurities in Semiconductors. John Wiley & Sons, New York, 1973, 526 p.