Vol. 4, 2019

Original research papers

Radiation Effects


Umutcan Gürer, Ercan Yilmaz

Pages: 156–161

DOI: 10.37392/RapProc.2019.32

In this study, the effects of gamma irradiation on the physical, electrochemical, and electrical properties of Dy2O3/p-Si thin films have been studied. For this, the rare earth oxide (Dy2O3) were deposited onto p-Si wafer by using an e-beam evaporation technique. The evolutions on the crystallographic and morphologic characteristics of the films under gamma irradiation were analyzed by X-ray diffraction (XRD) and Atomic Force Microscopy (AFM), respectively, while irradiation effects on the electrochemistry of the films were characterized by X-ray photoelectron spectroscopy (XPS). Furthermore, variations on the electrical characteristics of Dy2O3/p-Si thin films were also specified by Capacitance-Voltage (C-V) and Conductance-Voltage (G/ω-V) measurements. No significant changes on the crystallographic orientation were observed after gamma irradiation exposures. However, the grain size of the films was increased slightly due to the fact that the local heating aggregated the smaller grains into a bigger cluster. In addition, the surface roughness was increased after irradiation indicating that it deforms the films’ surface morphology. Two different intense intermixing phases revealed the presence of the electrochemical analysis of the virgin Dy2O3/p-Si thin films. These phases are Dysprosium sub-Oxide (DyxOy) and Oxygen deficient in Dy2O3 films. After irradiation exposures, Oxygen incorporation, vacancy, and interstitial defects formation were observed in the electrochemical characteristics of the films. On the other hand, the capacitance curves exhibit kinks in the region between depletion and accumulation due to the presence of the intermixing phases of Dy2O3 films. The capacitance of samples significantly increased with the increase of radiation doses, which are correlated with the generated interface state density and/or improvement of dielectric characteristics of Dy2O3 owing to Oxygen diffusion.
  1. F. B. Ergin, R. Turan, S. T. Shishiyanu, E. Yilmaz, “Effect of γ-radiation on HfO2 based MOS capacitor,” Nucl. Instrum. Methods Phys. Res., vol. 268, no. 9, pp. 1482 – 1485, May 2010.
    DOI: 10.1016/j.nimb.2010.01.027
  2. S. Kaya, E. Yilmaz, “A Comprehensive Study on the Frequency-Dependent Electrical Characteristics of Sm2O3 MOS Capacitors,” IEEE Trans. Electron Devices, vol. 62, no. 3, pp. 980 – 987, Jan. 2015.
    DOI: 10.1109/TED.2015.2389953
  3. Y. Li et al., “Study of γ-ray irradiation influence on TiN/HfO2/Si MOS capacitor by C-V and DLTS,” Superlattice. Microst., vol. 120, pp. 313 – 318, Aug. 2018.
    DOI: 10.1016/j.spmi.2018.05.046
  4. G. D. Wilk, R. M. Wallace, J. M. Anthony, “High-κ gate dielectrics: Current status and materials properties considerations,” J. Appl. Phys., vol. 89, no. 10, pp. 5243 – 5275, May 2001.
    DOI: 10.1063/1.1361065
  5. S. C. Chang, S. Y. Deng, J. Y. M. Lee, “Electrical characteristics and reliability properties of metal-oxide-semiconductor field-effect transistors with Dy2O3 gate dielectric,” Appl. Phys. Lett., vol. 89, no. 5, pp. 10 – 13, 2006.
    DOI: 10.1063/1.2217708
  6. A. Cherif et al., “The temperature dependence on the electrical properties of dysprosium oxide deposited on p-Si substrate,” Mater. Sci. Semicond. Process., vol. 29, pp. 143 – 149, Jan. 2015.
    DOI: 10.1016/j.mssp.2014.01.031
  7. M. Leskelä, K. Kukli, M. Ritala, “Rare-earth oxide thin films for gate dielectrics in microelectronics,” J. Alloys Compd., vol. 418, no. 1 – 2, pp. 27 – 34, Jul. 2006.
    DOI: 10.1016/j.jallcom.2005.10.061
  8. K. Xu et al., “Atomic Layer Deposition of Gd2O3 and Dy2O3: A Study of the ALD Characteristics and Structural and Electrical Properties,” Chem. Mater., vol. 24, no. 4, pp. 651 – 658, Feb. 2012.
    DOI: 10.1021/cm2020862
  9. A. Kahraman, E. Yilmaz, “Proposal of alternative sensitive region for MOS based radiation sensors: Yb2O3,” J. Vac. Sci. Technol. A, vol. 35, no. 6, Nov. 2017.
    DOI: 10.1116/1.4993545
  10. A. Kahraman, E. Yilmaz, “Irradiation response of radio-frequency sputtered Al/Gd2O3/p-Si MOS capacitors,” Radiat. Phys. Chem., vol. 139, pp. 114 – 119, Oct. 2017.
    DOI: 10.1016/j.radphyschem.2017.04.003
  11. A. Kahraman, E. Yilmaz, “A comprehensive study on usage of Gd2O3 dielectric in MOS based radiation sensors considering frequency dependent radiation response,” Radiat. Phys. Chem., vol. 152, pp. 36 – 42, Nov. 2018.
    DOI: 10.1016/j.radphyschem.2018.07.017
  12. S. Kaya, E. Yilmaz, A. Kahraman, H. Karacali, “Frequency dependent gamma-ray irradiation response of Sm2O3 MOS capacitors,” Nucl. Instrum. Methods Phys. Res., vol. 358, pp. 188 – 193, Sep. 2015.
    DOI: 10.1016/j.nimb.2015.06.037
  13. S. Abubakar, S. Kaya, H. Karacali, E. Yilmaz, “The gamma irradiation responses of yttrium oxide capacitors and first assessment usage in radiation sensors,” Sens. Actuator A-Phys., vol. 258, pp. 44 – 48, May 2017.
    DOI: 10.1016/j.sna.2017.02.022
  14. F. C. Chiu, “Electrical characterization and current transportation in metal ∕ Dy2O3 ∕ Si structure,” J. Appl. Phys., vol. 102, no. 4, Aug. 2007.
    DOI: 10.1063/1.2767380
  15. [ A. A. Dakhel, “Annealing effect on the dc transport mechanism in dysprosium oxide films grown on Si substrates,” J. Electron. Mater., vol. 35, no. 7, pp. 1547 – 1551, Jul. 2006.
    DOI: 10.1007/s11664-006-0147-4
  16. T. M. Pan, W. T. Chang, F. C. Chiu, “Structural properties and electrical characteristics of high-k Dy2O3 gate dielectrics,” Appl. Surf. Sci., vol. 257, no. 9, pp. 3964 – 3968, Feb. 2011.
    DOI: 10.1016/j.apsusc.2010.11.144
  17. M. Chakraverty, H. M. Kittur, “Comparison of tunnel currents through SiO2, HfO2, Ta2O5, ZrO2 and Dy2O3 dielectrics in MOS devices for ultra large scale integration using first principle calculations,” in Proc. 2013 Annu. Int. Conf. Emerg. Res. Areas (AICERA 2013) and 2013 Int. Conf. Microelectron. Commun. Renew. Energy (ICMiCR 2013), Kanjirapally, India, 2013.
    DOI: 10.1109/AICERA-ICMiCR.2013.6575936
  18. K. Lawniczak-Jablonska et al., “Surface morphology of DyxOy films grown on Si,” Appl. Surf. Sci., vol. 253, no. 2, pp. 639 – 645, Nov. 2006.
    DOI: 10.1016/j.apsusc.2005.12.150
  19. S. Kaya, I. Yıldız, R. Lok, E. Yılmaz, “Co-60 gamma irradiation influences on physical, chemical and electrical characteristics of HfO2/Si thin films,” Radiat. Phys. Chem., vol. 150, pp. 64 – 70, Sep. 2018.
    DOI: 10.1016/j.radphyschem.2018.04.023
  20. S. Kaya, E. Yilmaz, “Modifications of structural, chemical, and electrical characteristics of Er2O3/Si interface under Co-60 gamma irradiation,” Nucl. Instrum. Methods Phys. Res., vol. 418, pp. 74 – 79, Mar. 2018.
    DOI: 10.1016/j.nimb.2018.01.010
  21. M. Ishfaq et al., “Optical and electrical characteristics of 17 keV X-rays exposed TiO2 films and Ag/TiO2/p-Si MOS device,” Mater. Sci. Semicond. Process., vol. 63, pp. 107 – 114, Jun. 2017.
    DOI: 10.1016/j.mssp.2017.02.009
  22. L. Vlasukova et al., “Photoluminescence and enhanced chemical reactivity of amorphous SiO2 films irradiated with high fluencies of 133-MeV Xe ions,” Vacuum, vol. 141, pp. 15 – 21, Jul. 2017.
    DOI: 10.1016/j.vacuum.2017.03.007
  23. K. Agashe et al., “Effect of gamma irradiation on resistive switching of Al/TiO2/n+Si ReRAM,” Nucl. Instrum. Methods Phys. Res., vol. 403, pp. 38 – 44, Jul. 2017.
    DOI: 10.1016/j.nimb.2017.04.091
  24. B. M. Abu-Zied, A. M. Asiri, “Synthesis of Dy2O3 nanoparticles via hydroxide precipitation: effect of calcination temperature,” J. Rare Earths, vol. 32, no. 3, pp. 259 – 264, Mar. 2014.
    DOI: 10.1016/S1002-0721(14)60061-2
  25. B. L. Doyle, Displacement Damage Caused by Gamma-rays and Neutrons on Au and Se, Rep. SAND2014-19440 R, Sandia National Laboratories, Albuquerque (NM), USA, 2014.
    DOI: 10.2172/1177090
  26. I. G. Madiba et al., “Effects of gamma irradiations on reactive pulsed laser deposited vanadium dioxide thin films,” Appl. Surf. Sci., vol. 411, pp. 271 – 278, Jul. 2017.
    DOI: 10.1016/j.apsusc.2017.03.131
  27. Y. Jun-Feng et al., “The first-principles calculation of the effects oxygen defect on the electronic structure of SnO2,” in Proc. 2008 2nd IEEE International Nanoelectronics Conference, Shanghai, China, 2008.
    DOI: 10.1109/INEC.2008.4585569
  28. B. C. Lan, J. J. Hsu, S. Y. Chen, J. S. Bow, “Forming gas annealing on physical characteristics and electrical properties of Sr0.8Bi2Ta2O9/Al 2O3/Si capacitors,” J. Appl. Phys., vol. 94, no. 3, pp. 1877 – 1881, Aug. 2003.
    DOI: 10.1063/1.1588362
  29. A. Tataroğlu et al., “Electronic and optoelectronic properties of Al/coumarin doped Pr2Se3–Tl2Se/p-Si devices,” J. Mater. Sci.: Mater. Electron., vol. 29, no. 15, pp. 12561 – 12572, Aug. 2018.
    DOI: 10.1007/s10854-018-9372-x
  30. W. A. Hill, C. C. Coleman, “A single-frequency approximation for interface-state density determination,” Solid. State. Electron., vol. 23, no. 9, pp. 987 – 993, Sep. 1980.
    DOI: 10.1016/0038-1101(80)90064-7