Journal of Physical Studies 25(3), Article 3705 [4 pages] (2021)
DOI: https://doi.org/10.30970/jps.25.3705

THE INFLUENCE OF SULPHIDE SURFACE MODIFICATION REGIMES ON THE MECHANISM OF CURRENTS IN p–n JUNCTIONS BASED ON GaAs

N. V. Masleyeva1, O. V. Bogdan2, I. V. Brytavskyi1, D. V. Tarasevich2, V. V. Shugarova3

1Odesa I. I. Mechnikov National University, Department of Experimental Physics,
42, Pasteur St., Odesa, UA–65023, Ukraine
2Odesa State Academy of Building and Architecture, 4, Didrikhson St., Odesa, UA–65029, Ukraine
3Physical-chemical Institute for Environment and Human Protection, Ministry of Education and Science, NAS of Ukraine,
3, Preobrazhenska St., Odesa, UA–65082, Ukraine

Received 15 May 2019; in final form 03 June 2021; accepted 04 June 2021; published online 10 August 2021

Sulphide modification of gallium arsenide involves both chemical and electronic passivation of the surface. It results in a complete or partial removal of surface oxides, the surface reconstruction and the formation of a passivating layer Ga$_2$S$_3$. Such treatment decreases the density of surface states, reduces the speed of the surface recombination and slows down the speed of the surface oxides formation. It leads to a significant improvement in the characteristics of the semiconductor devices based on GaAs. The lack of studies on the duration and conditions of sulphide surface modification and its efficiency narrows possibilities for using this treatment to improve characteristics of GaAs as well as semiconductor devices based on it.

This work studied the influence of sulphide surface modification modes on the volt-ampere characteristics of $p$-$n$ junctions based on GaAs which were obtained by epitaxial extension of GaAs(Si) on the substrate GaAs(Te). To increase the ability to control changes in the V-A characteristics, an aqueous solution of sodium sulphide was used, in which a passivating coating forms slower than in alcohol solutions. An additional slowdown of the sulphide passivation process was achieved by reducing the concentration of sulphide ions in the solution. The given results were obtained after the modification of the surface by sulphur atoms in a 300x0p+0queous solution of sodium sulphide under illumination with focused light from an incandescent lamp.

It was found that a short-term treatment reduces direct and reverse currents in the pre-breakdown area, which is the result of a decrease in the density of surface states at the edge of the division of $p$- and $n$-areas. With an increase in the duration of the treatment, the effect of improving the V-A characteristics decreased. At some point of the treatment, the changes in the currents reached their peak and then started to decline. This can be explained by the increase in the density of surface states of the $p$-$n$ junctions, which occurs with an increase in the thickness of the passivating layer of gallium sulphide during a long-term treatment. This process occurs both on the surfaces that are coplanar to the epitaxial one and at the edges. Since the values of the series resistance of the studied diodes during such treatments did not change, the main role in the changes of the currents during a long-term treatment was played by the processes at the edge surfaces of the diodes. Due to a mismatch between the parameters of the lattice Ga$_2$S$_3$ formed on the surface and large GaAs, additional mechanical tensions appear leading to an increase in the density of the surface states of the $p$-$n$ junctions. This is accompanied by an increase in short-circuit currents. Therefore, with an increase in the duration of sulphide surface treatment, no further improvement of the V-A characteristics occurs. The fact that the changes in the currents reach their peak at a certain point during the sulphide modification of the surface and then start to decline must be taken into account to optimize the duration of the treatment in order to achieve the biggest improvement in the V-A characteristics of $p$-$n$ junctions based on GaAs.

Key words: $p$–$n$ junction, gallium arsenide, sulphur atoms, surface modification, surface oxide, aqueous solution of sodium sulphide, direct and reverse current, surface states, surface reconstruction, passivating layer of gallium sulphide

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References
  1. С. С. Хлудков, О. П. Толбанов, М. Д. Вилисова, И. А. Прудаев, Полупроводниковые приборы на основе арсенида галлия с глубокими примесными центрами (Издат. дом Томского гос. ун-та, Томск, 2016).
  2. Б. И. Бедный, Вестн. Нижегород. ун-та им. Н. И. Лобачевского. Сер. Физ. тверд. тела №1, 78 (2000).
  3. M. V. Lebedev, Semiconductors 54, 699 (2020);
    Crossref
  4. V. N. Bessolov, M. V. Lebedev, Semiconductors 32, 1141 (1998);
    Crossref
  5. Л. О. Mатвєєва, О. Ю. Колядіна, І. М. Матіюк, О. М. Міщук, Фіз. хім. тверд. тіла 7, 461 (2006).
  6. M. V. Lebedev, V. V. Sherstnev, E. V. Kunitsyna, I. A. Andreev, Yu. P. Yakovlev, Semiconductors 45, 526 (2011);
    Crossref
  7. R. W. Lambert et al., J. Light. Technol. 24, 956 (2006);
    Crossref
  8. V. N. Bessolov, E. V. Konenkova, M. V. Lebedev, D. R. T. Zahn, Phys. Solid State 41, 793 (1999);
    Crossref
  9. V. N. Bessolov, E. V. Konenkova, M. V. Lebedev, Mater. Sci. Eng. B 44, 376 (1997);
    Crossref
  10. M. V. Lebedev, Semiconductors 35, 1291 (2001);
    Crossref
  11. В. Н. Бессолов, М. В. Лебедев, Т. В. Львова, Е. Б. Новиков, Физ. тверд. тела 34, 1713 (1992).
  12. V. N. Bessolov, E. V. Konenkova, M. V. Lebedev, Phys. Solid State 39, 54 (1997);
    Crossref
  13. Л. М. Коган, Полупроводниковые светоизлучающие диоды (Энегроатомиздат, Москва, 1983).
  14. С. М. Зи, Физика полупроводникових приборов (Мир, Москва, 1984).
  15. V. V. Evstropov et al., Semiconductors 34, 1305 (2000);
    Crossref
  16. C. H. Henry, R. A. Logan, F. R. Merritt, J. Appl. Phys. 49, 3530 (1978);
    Crossref
  17. А. А. Ptashchenko, F. А. Ptashchenko, Proc. SPIE 3182, 152 (1997);
    Crossref