The effect of germanium wetting layer on the percolation processes in ultrathin copper films and their microwave transmission, reflection and absorption coefficients

Cover Page

Cite item

Full Text

Open Access Open Access
Restricted Access Access granted
Restricted Access Subscription or Fee Access

Abstract

The microwave coefficients of copper films with a thickness of 1...16 nm grown on a 1.8 nm germanium sublayer deposited on the surface of quartz glass substrates with a thickness of 4 mm are studied. The measurements have been carried out in a rectangular waveguide with a cross section of 23×10 mm2 in the frequency range of 8.5...12.5 GHz. A smooth change in the microwave coefficients of the samples studied is detected in the range of copper film thicknesses of 2...16 nm. It is established that the critical percolation thickness of the copper films grown on germanium sublayer is in the range between 1 and 2 nm. A significant internal size effect is found in the films grown on Ge sublayer due to the scattering of conduction electrons mainly by intercrystalline boundaries. It is determined that the coefficient of reflection of conduction electrons by the intercrystalline boundaries of the copper films with Ge sublayer is more than three times higher than a similar coefficient in Cu films grown directly on the glass substrates.

Full Text

Restricted Access

About the authors

V. A. Vdovin

Kotel’nikov Institute of Radio Engineering and Electronics of RAS

Author for correspondence.
Email: vdv@cplire.ru
Russian Federation, Mokhovaya, 11, building 7, Moscow, 125009

V. G. Andreev

Kotel’nikov Institute of Radio Engineering and Electronics of RAS

Email: vdv@cplire.ru
Russian Federation, Mokhovaya, 11, building 7, Moscow, 125009

I. I. Pyataikin

Kotel’nikov Institute of Radio Engineering and Electronics of RAS

Email: vdv@cplire.ru
Russian Federation, Mokhovaya, 11, building 7, Moscow, 125009

Yu. V. Pinaev

Kotel’nikov Institute of Radio Engineering and Electronics of RAS

Email: vdv@cplire.ru
Russian Federation, Mokhovaya, 11, building 7, Moscow, 125009

References

  1. Каплан А. Е. // РЭ. 1964. Т. 9. № 10. С. 1781.
  2. Kaplan A. E. // J. Optical Soc.Am. B. 2018. V. 35. № 6. P. 1328. doi: 10.1364/JOSAB.35.001328
  3. Khorin I., Orlikovsky N., Rogozhin A. et al. // Proc. SPIE. 2016. V. 10224. Р. 1022407–1. doi: 10.1117/12.2266504
  4. Fuchs K. // Mathematical Proc. Cambridge Philosophical Soc. 1938. V. 34. № 1. P. 100. doi: 10.1017/S0305004100019952
  5. Dingle R. B. // Proc. Royal Soc. A. 1950. V. 201. № 1067. P. 545. doi: 10.1098/rspa.1950.0077
  6. Sondheimer E. H. // Adv. Phys. 1952. V. 1. № 1. P. 1. doi: 10.1080/00018735200101151
  7. Mayadas A. F., Shatzkes M., Janak J. F. // Appl. Phys. Lett. 1969. V. 14. № 11. P. 345. doi: 10.1063/1.1652680
  8. Mayadas A. F., Shatzkes M. // Phys. Rev. B. 1970. V. 1. № 4. P. 1382. doi: 10.1103/PhysRevB.1.1382
  9. Camacho J. M., Oliva A. I. // Thin Solid Films. 2006. V. 515. P. 1881. doi: 10.1016/j.tsf.2006.07.024
  10. Андреев В. Г., Вдовин В. А., Глазунов П. С. и др. // Оптика и спектроскопия. 2022. Т. 130. № 9. С. 1410. doi: 10.21883/OS.2022.09.53304.3539–22
  11. Barmak K., Darbal A., Ganesh K. J. et al. // J. Vacuum Sci. Technol. A. 2014. V. 32. № 6. P. 061503–1. doi: 10.1116/1.4894453
  12. Вдовин В. А., Андреев В. Г., Глазунов П. С. и др. // Оптика и спектроскопия. 2019. Т. 127. № 5. С. 834. doi: 10.21883/OS.2019.11.48524.132–19

Supplementary files

Supplementary Files
Action
1. JATS XML
Download
2. Fig. 1. Frequency dependences of microwave coefficients R, T and A of copper film for two wave incidence geometries: wave incidence from the substrate side (a) and wave incidence from the film side (b); symbols are coefficients of copper film 7.9 nm thick, deposited directly on a quartz glass substrate, solid curves are values ​​of similar coefficients for Cu film of the same thickness, but grown on a germanium sublayer.

Download (29KB)
Indexing metadata
3. Fig. 2. Dependences of the coefficients R, T and A on the thickness of the copper film grown on the Ge sublayer, measured at a frequency of 11.5 GHz, for the case of wave incidence from the film side (a) and from the substrate side (b).

Download (30KB)
Indexing metadata
4. Fig. 3. Measured at a frequency of 11.5 GHz, the dependences of the coefficients R, T and A on the thickness of the copper film grown on a substrate with a Ge sublayer (filled symbols) and in its absence (outline symbols). The dependences shown in the figure correspond to the case of microwave incidence from the substrate.

Download (19KB)
Indexing metadata
5. Fig. 4. A continuous 5 nm Cu film grown on a 1.8 nm thick germanium sublayer deposited on the SiO2 surface of conductive silicon (a) and an island-like 5 nm thick Cu film on the SiO2 surface of conductive silicon (b).

Download (31KB)
Indexing metadata
6. Fig. 5. Dependence of the dc conductivity of copper films grown on a substrate with a Ge sublayer (dots) on the thickness; the line indicates the result of fitting the experimental points using formula (1) with a fixed parameter σ0 = 5.95⋅105 S/cm.

Download (11KB)
Indexing metadata

Copyright (c) 2024 Russian Academy of Sciences