Home > ajphysmat.uz > Vol. 1 > Iss. 1 (2019)

## Scientific Bulletin. Physical and Mathematical Research

#### Abstract

It possibility of determining the dominant generation mechanisms, as well as to estimate the generation-recombination parameters from the analysis and comparison of experimental and theoretical dependences is shown in the paper. An expression for the total rate of recombination is obtained, which describes the process of relaxation of the MIS capacitance of the structure during the formation of the charge of the inversion layer of the shift voltage. The obtained calculated time dependence of the OPZ width can be used to determine the values of the velocity of surface and volume generation of charge carriers when compared with its experimental dependence. Another variant of the pulsed method for studying the electrical properties of the semiconductor - dielectric interface is presented. It is based on the measurement of the Farad characteristics of the metal-dielectric-semiconductor structure at different rates of the applied voltage change, which is based on the assumption that at high rates of the applied voltage change only the main charge carriers have time to follow the changes in the applied voltage. While at sufficiently low rates of applied voltage surface States have time to recharge, exchanging electrons with the permitted energy zones. The frequency of the alternating test signal is chosen high enough to ignore the contribution to the measured charge capacity of non-primary carriers. This gives is the opportunity to waitforany hysteresis characteristics to determine the density of surface States, averaged across the width of the forbidden zone of the semiconductor. The proposed method makes it possible to determine the charge localized on the surface States by the magnitude of the shift of two pulse characteristics along the stress axis at a certain value of the structure capacitance. The charge of surface States is determined by the expression Qss(C)=C0(U1-U2), where C0 is the dielectric capacitance, U1, U2 are the voltage values at some capacitance value equal to C. The main advantage of the pulse method, in comparison with the method of C-V characteristics is that the high rate of voltage rise and large duty cycle, makes it possible to use this method to study the interface semiconductor-dielectric, in which the dielectric contains different charges. Moreover, the determination of the density of surface States does not depend on the distribution of a fixed charge in the dielectric, which is a source of error when using high-frequency and low-frequency capacitive methods. The pulse method allows to determine the energy distribution of the surface States and at voltages corresponding to the inversion of the surface conductivity, i.e. in a wider part of the band gap of the semiconductor. The obtained expression, describing relaxation of the capacitance of mos structures during the formation of a charge inversion layer after switching the offset direction V1V2. This equation is the equation of a straight line in coordinates x=(C_ct/C(t) -1) 1/C_ct ; y=1/C^3 dC/dt, that is, equations of the form y=ax+b. The surface generation velocity Sg, and the lifetime of minority carriers g is determined from the tangent of the angle dependence of a and the coefficient b determines the shift of dependencies along the axis of the 1/C^3 dC/dt. The slope angle tangent is directly proportional to the lifetime of the main charge carriers in a semiconductor.

#### First Page

14

#### Last Page

26

#### References

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#### Recommended Citation

Karimov, I.N.; Nosirov, M.Z.; Fozilzhonov, M.B.; and M.A. Ergasheva
(2019)
"GENERATION-RECOMBINATION CHARACTERISTICS OF THE INTERFACE OF Si-SiO2 STRUCTURES,"
*Scientific Bulletin. Physical and Mathematical Research*: Vol. 1
:
Iss.
1
, Article 3.

Available at:
https://uzjournals.edu.uz/adu/vol1/iss1/3