A.V. Voitsekhovskii - Dr.Sc. (Phys.-Math.), Head of Department, National Research Tomsk State University E-mail: vav43@mail.tsu.ru N.A. Kulchitsky - Dr.Sc. (Eng.), Professor, Moscow Technological University (MIREA), Lomonosov Moscow State University E-mail: n.kulchitsky@gmail.com S.N. Nesmelov - Ph.D. (Phys.-Math.), Senior Research Scientist, National Research Tomsk State University E-mail: nesm69@mail.ru S.M. Dzyadukh - Ph.D. (Phys.-Math.), Research Scientist, National Research Tomsk State University E-mail: bonespirit@sibmail.com

The admittance of MIS structures based on n(p)-Hg_1-xCd_xTe (x = 0.21-0.23) grown by molecular beam epitaxy on substrates of GaAs (013) and Si (013) was considered. The possibilities of determining the main parameters of nanoscale transition layer on the insulator-semiconductor interface (densities of fast and slow interface states, concentration of donor-type native defects) for MIS structures based on n(p)-Hg_1-xCd_xTe (x = 0.21-0.23) with and without graded-gap layers from admittance measurement in wide temperature and frequency ranges were discussed. It is shown that the capacitance-voltage characteristics of MIS structures based on n(p)-Hg_1-xCd_xTe (x = 0.21...0.23) with near-surface graded-gap layers demonstrate a high-frequency behavior with respect to time recharge of surface states at 77 K in wide frequency range. This allows you to determine the concentration of the dopant in the near-surface semiconductor layer using a capacitance value at a minimum of experimental capacitance-voltage characteristics. Spectrum fast surface states at the interface can be found for MIS structures based on HgCdTe with graded-gap layer using a high-frequency method. It was found that the MIS structure based on n-HgCdTe without graded-gap layer at low temperatures (9-15 K) and frequencies of 200 kHz have a high-frequency capacitance-voltage characteristics relatively recharge of fast surface states located near the Fermi level for intrinsic semiconductor. This makes it possible to determine the concentration of electrons at low temperatures, and then estimate using low-frequency method the density of fast surface states at 77 K. The MIS structures based on p-HgCdTe without graded-gap layer at low temperatures have large value of series resistance of epitaxial film making it difficult to measure admittance at low temperatures.

 

1. Rogalski A. Infrared detectors, 2nd ed.. New York: CRC Press. 2011.876 p.
2. Sidorov JU.G., Dvoreckijj S.A., Varavin V.S. i dr. Molekuljarno-luchevaja ehpitaksija tverdykh rastvorov kadmijj-rtut-tellur na «alternativnykh» podlozhkakh // FTP. 2001. T. 35. № 9. S. 1092‒1101.
3. Izhnin I.I., Nesmelov S.N., Dzyadukh S.M. et al. Admittance Investigation of MIS Structures with HgTe-Based Single Quantum Wells // Nanoscale Research Letters. 2016. V. 11. № 1. P. 53-1‒53-4.
4. Fu R., Pattison J. Advanced thin conformal Al2O3 films for high aspect ratio mercury cadmium telluride sensors // Optical Engineering. 2012. V. 51. № 10. P. 104003-1‒104003-4.
5. Vojjcekhovskijj A.V., Nesmelov S.N., Dzjadukh S.M. Gisterezisnye javlenija v MDP-strukturakh na osnove varizonnogo MLEH HgCdTe s dvukhslojjnym plazmokhimicheskim diehlektrikom SiO2/Si3N4 // Izvestija vuzov. Fizika. 2015. T. 58. № 4. S. 97‒106.
6. Nicollian E. H., Brews J. R. MOS (metal oxide semiconductor) physics and technology. New York: Wiley. 1982. 906 p.
7. Goodwin M.W., Kinch M.A., Koestner R.J. Metal-insulator semiconductor properties of molecular-beam epitaxy grown HgCdTe heterostructures // Journal of Vacuum Science & Technology A. 1990. V. 8. № 2. P. 1226‒1232.
8. Goodwin M.W., Kinch M.A., Koestner R.J. Metal-insulator-semiconductor properties of HgTe-CdTe superlattices // Journal of Vacuum Science & Technology A. 1988. V. 6. № 4. P. 2685‒2692.
9. Ovsjuk V.N., JArcev A.V. Issledovanie volt-faradnykh kharakteristik MDP-struktur na osnove MLEH CdHgTe n- i r-tipa // Prikladnaja fizika. 2007. № 5. S. 80‒83.
10. Vasilev V.V., Mashukov JU.P. Volt-faradnye kharakteristiki struktur na osnove p-Cd0.27Hg0.73Te s shirokozonnym varizonnym sloem na poverkhnosti // FTP. 2007. T. 41. № 1. S. 38‒44.
11. An S.Y., Kim J.S., Seo D.W. et al. Passivation of HgCdTe pn diode junction by compositionally graded HgCdTe formed by annealing in a Cd/Hg atmosphere // Journal of Electronic Materials. 2002. V. 31. № 7. P. 683‒687.
12. Rosbeck J.P., Harper M.E. Doping and composition profiling in Hg1−xCdxTe by the graded capacitance-voltage method // Journal of Applied Physics. 1987. V. 62. № 5. P. 1717‒1722.
13. Voitsekhovskii A., Nesmelov S., Dzyadukh S. Influence of composition of the near-surface graded-gap layer on the admittance of metal-insulator-semiconductor structures based on graded-gap MBE n-Hg1−xCdxTe in wide temperature range // Opto-Electronics Review. 2014. V. 22. № 4. P. 236‒244.
14. Vojjcekhovskijj A.V., Nesmelov S.N., Dzjadukh S.M. i dr. Raschet volt-faradnykh kharakteristik MDP-struktur na osnove GEHS HgCdTe MLEH s pripoverkhnostnymi varizonnymi slojami s povyshennym sostavom // Prikladnaja fizika. 2011. № 5. S. 80‒86.
15. Voitsekhovskii A.V., Nesmelov S.N., Dzyadukh S.M. Capacitance-voltage characteristics of metal-insulator-semiconductor structures based on graded-gap HgCdTe with various insulators // Thin Solid Films. 2012. V. 522. P. 261‒266.
16. Sze S.M., Ng Kwok K. Physics of Semiconductor Devices, 3rd ed.. New York : Wiley, 2007. 832 p.
17. Voitsekhovskii A.V., Nesmelov S.N., Dzyadukh S.M. Dopant in Near-Surface Semiconductor Layers of Metal-Insulator-Semiconductor Structures Based on Graded-Gap p-Hg0.78Cd0.22Te Grown by Molecular-Beam Epitaxy // Journal of Electronic Materials. 2016. V. 45. № 2. P. 881‒891.
18. Frankl D.R. Some effects of material parameters on the design of surface space-charge varactors // Solid-State Electronics. 1961. V. 2. № 1. P. 71‒76.
19. Van Overstraeten R., Declerck G., Broux G. Graphical Technique to Determine the Density of Surface States at the Si/SiO2 Interface of MOS Devices Using the Quasistatic C-V Method // Journal of The Electrochemical Society. 1973. V. 120. № 12. P. 1785‒1787.