MEASUREMENTS OF SILICON CONDUCTIVITY BY MEANS FREQUENCY FIGURES IN MICROWAVE REGION

UDC 537.633.2

 

. Madiyarov Vladimir Rafkatovich – PhD (Physics and Mathematics), Associate Professor, Assistant Professor, the Department of Physics. Belarusian State Technological University (13a, Sverdlova str., 220006, Minsk, Republic of Belarus). E-mail: Madyarov@belstu.by

 

DOI: https://doi.org/ 10.52065/2520-6141-2023-272-2-9 (In Russian).

 

Key words: microwave radiation, waveguide, electromagnetic waves, transmission coefficient, specific conductivity.

 

For citation: Madyarov V. R. Measurements of silicon conductivity by means frequency figures in microwave region. Proceedings of BSTU, issue 3, Physics and Mathematics. Informatics, 2023, no. 2 (272), pp. 53–57. DOI: 10.52065/2520-6141-2023-272-2-9 (In Russian).

 

Abstract

Measurements of intensity of the radiation passed through semiconductor wafer provide the information on conductivity of the sample material to be probed. Microwave radiation transmission coefficient of the medium depends on dielectric permeability and specific conductivity of the medium. Estimation shows that for the majority of widely used semiconductors with conductivity σ > 30 S/m it is possible to allocate frequency range 20–80 GHz where frequency response of probing radiation transmission coefficient is very close to the linear. Specific conductivity is possible to calculate using slope of the measured linear dependence. Comparison between the data obtained for wafers of two different thicknesses shows that measured results are considerably influenced by multiple internal reflections from both sides of the sample when the wavelength becomes comparable with sample thickness. In addition, cancellation due to interference between incident and reflected waves may also be effective. Therefore, samples for measurements are appropriately used with thickness that much less comparable to probing wavelength. Specific conductivity values obtained by means of linear part of frequency response for silicon wafers in the region 40–75 GHz are in good agreement with the estimated data of intrinsic conductivity of the probed sample at room temperatures if Boltzman distribution is assumed for charge carriers.

 

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References

 

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Поступила после доработки 15.03.2023