THE METHOD OF SEPARATE DETERMINATION OF HIGH−OHMIC SAMPLE RESISTANCE AND CONTACT RESISTANCE

The method of separate determination of two−pole sample volume resistance and contact resistance is suggested. The method described is applicable to high−ohmic semiconductor samples: semiinsulating gallium arsenide, detector cadmium−zinc tel- luride (CZT), etc. The method is based on near−contact region illumination by monochromatic radiation of variable intensity from light emitting diodes with quantum energy exceeding band gap width of investigated material. It is necessary to obtain sample photo−current dependence upon light emitting diode current and to find the straight−line part of this dependence. The extrapola- tion of this linear part to ordinate axis gives cut−off current value. As bias voltage is known, it is easy to calculate sample volume resistance value. Afterwards, using dark current value, it is pos- sible to determine total contact resistance. The method was approbated on n−type semiinsulating GaAs sample. Contact resistance value was shown to be approximately equal to sample volume resistance. It means that influence of contacts must be taken into account when electrophysical data is analyzed.

1. Jaeger, H. Transition resistances of ohmic contacts to p−type CdTe and their time−dependent variation / H. Jaeger, E. Seipp // J. Electron. Mater. − 1981. − V. 10, N 3. − P. 605—618.

2. Brinkman, A. W. Contacts to Cd/Zn/Te/Se compounds / A. W. Brinkman // Properties of Narrow Gap Cadmium−Based Com- pounds. − London (UK) : INSPEC, 1994. − P. 575—581.

3. Br un , D. L ow resi st ance ohm ic cont act on n − CdTe / D. Brun, B. Daudin, E. Ligeon // Appl. Phys. Lett. − 1994. − V. 65, N 4. − P. 475—477.

4. Klevkov, Yu. V. Vliyanie passivacii poverhnosti p− CdTe v (NH4)2Sx na vol’t−ampernye harakteristiki kontaktov / Yu. V. Klevk- ov, S. A. Kolosov, A. F. Plotnikov // Fizika i tehnika poluprovodnikov. − 2006. − T. 40, Iss. 9. − P. 1074—1078.

5. Blank, T. V. Mehanizm protekaniya toka v omicheskih kontaktah metall—poluprovodnik / T. V. Blank, Yu. A. Gol’dberg // Ibid. − 2007. − T. 41, Iss. 11. − P. 1281—1308.

6. Kovalev, A. N. Sovremennye metody usovershenstvovaniya polevyh AlGaN/GaN−geterotranzistorov / A. N. Kovalev // Izv. vu- zov. Materialy elektron. tehniki. − 2007. − N 2. − P. 4—17.

7. Vi k u l i n , I . M . Fizika polupr ovodn i kov yh pr ib or ov / I. M. Vikulin, V. I. Stafeev. − M. : Sovetskoe radio, 1980. − P. 22.

8. Stafeev, V. I. Termoelektricheskie i drugie yavleniya v strukturah s neravnovestnymi nositelyami zaryada i nanochasticami / V. I. Stafeev // Fizika i tehnika poluprovodnikov. − 2009. T. 43, Iss. 5. − P. 636—639.

9. Ruzin, A. Simulation of Schottky and ohmic contacts on CdTe / A. Ruzin // J. Appl. Phys. − 2011. − V. 109, Iss. 1. − P. 014509.

10. Mahnii, V. P. Poluizoliruyushie sloi tellurida kadmiya / V. P. Mahnii // Zhurnal tehn. fiziki. − 2005. T. 75, Iss. 11. − P. 122— 123.

11. Kosyachenko, L. A. Osobennosti mehanizma elektroprovod- nosti poluizoliruyushih monokristallov CdTe / L. A. Kosyachenko, O. L. Maslyanchuk, S. V. Mel’nichuk, V. M. Sklyarchuk, O. V. Sklyarchuk, T. Aoki // Fizika i tehnika poluprovodnikov. − 2010. − T. 44, Iss. 6. − P. 729—734.

12. Belyaev, A. P. Vliyanie metoda sinteza na svoistva plenok tellurida kadmiya, sintezirovannyh v rezko neravnovesnyh usloviyah / A. P. Belyaev, V. P. Rubec, V. V. Antipov, E. O. Eremina // Ibid. − 2010. T. 44, Iss. 7. − P. 978—980.

13. Kosyachenko, L. A. Self−compensation limited conductivity in semi−insulating indium−doped Cd0.9Zn0.1Te crystals / L. A. Kosyachenko, S. V. Melnychuk, O. L. Maslyanchuk, V. M. Sklyarchuk, O. F. Sklyarchuk, M. Fiederle, C. P. Lambropoulos // J. Appl. Phys. − 2012. − V. 112. − P. 013705.

14. Kolosov, S. A. Povedenie Bi v reshetke CdTe i effekt kompensacii v CdTe : Bi / S. A. Kolosov, V. S. Krivobok, Yu. V. Klevkov, A. F. Adiyatullin // Fizika i tehnika poluprovodnikov. − 2013. − T. 47, Iss. 4. − P. 538—545.

15. Golubyatnikov, V. A . Fotoemissiya svobodnyh nositelei zaryada v vysokoomnyi poluprovodnik pri osveshenii omicheskih kontaktov / V. A. Golubyatnikov, A. G. Belov, F. I. Grigor’ev, A. P. Lysenko, N. I. Strogankova, M. B. Shadov // Materialy XX yu-einoi nauchno−tehn. konf. «Vakuumnaya nauka i tehnika». − M., 2013. − P. 220—222; 358.