Browsing by Author "Gritsenko, V. A."

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Atomic and Electronic Structures of a-SiNx:H
(2019-11-01)
Gritsenko, V. A.
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Kruchinin, V. N.
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Prosvirin, I. P.
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Novikov, Yu N.
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Chin, A.
The atomic structure and the electronic spectrum of a-SiNx:H films, which are grown by plasmachemical deposition with varied ammonia and monosilane flow rates, are studied. As a result of varied flow rates, stoichiometric parameter x is changed over wide limits, from 0.73 to 1.33. The films are analyzed by structural and optical techniques to determine stoichiometric parameter x and its influence on the valence band top and the band gap in the density of states. The experimental and calculated electronic structure parameters of a-SiNx are compared, and good agreement between them is achieved over wide film composition (parameter x) limits. The experimental data obtained can be used to simulate the electron transport characteristics in nonstoichiometric silicon nitride films, which is important for creating memristors based on them.
Bipolar conductivity in amorphous HfO(2)
(2011-08-15)
Islamov, D. R.
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Gritsenko, V. A.
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Cheng, C. H.
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Chin, A.
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交大名義發表
This study calculates the contribution of electrons and holes to HfO(2) conductivity in Si/HfO(2)/Ni structures using experiments on injection of minority carriers from n- and p-type silicon. Results show that electrons and holes contribute to the conductivity of HfO(2), allowing HfO(2) to exhibit two-band conductivity. (C) 2011 American Institute of Physics. [doi:10.1063/1.3626599]
Bipolar conductivity in amorphous HfO2
(2011-08-15)
Islamov, D. R.
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Gritsenko, V. A.
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Cheng, C. H.
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Chin, A.
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交大名義發表
This study calculates the contribution of electrons and holes to HfO2 conductivity in Si/HfO2/Ni structures using experiments on injection of minority carriers from n- and p-type silicon. Results show that electrons and holes contribute to the conductivity of HfO2, allowing HfO2 to exhibit two-band conductivity. (C) 2011 American Institute of Physics. [doi:10.1063/1.3626599]
Bipolar conductivity in nanocrystallized TiO2
(1970-01-01)
Islamov, D. R.
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Gritsenko, V. A.
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Cheng, C. H.
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Chin, A.
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交大名義發表
"This study calculated the contribution of electrons and holes to TiO2 conductivity in Si/TiO2/Ni structures by conducting experiments on the injection of minority carriers from n- and p-type silicon. Results show that electrons and holes contribute to the conductivity of TiO2, enabling two-band conductivity. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4737016]"
Charge transport in amorphous Hf0.5Zr0.5O2
(2015-03-09)
Islamov, D. R.
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Perevalov, T. V.
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Gritsenko, V. A.
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Cheng, C. H.
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Chin, A.
In this study, we demonstrated experimentally and theoretically that the charge transport mechanism in amorphous Hf0.5Zr0.5O2 is phonon-assisted tunneling between traps like in HfO2 and ZrO2. The thermal trap energy of 1.25 eV and optical trap energy of 2.5 eV in Hf0.5Zr0.5O2 were determined based on comparison of experimental data on transport with different theories of charge transfer in dielectrics. A hypothesis that oxygen vacancies are responsible for the charge transport in Hf0.5Zr0.5O2 was discussed. (C) 2015 AIP Publishing LLC.
Charge transport mechanism in SiNx-based memristor
(2019-12-16)
Gismatulin, A. A.
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Gritsenko, V. A.
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Yen, T-J
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Chin, A.
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電子工程學系及電子研究所
Amorphous silicon nitride is a key dielectric in silicon devices. The advantage of SiNx and Si3N4 over other dielectrics is that silicon nitride is compatible with silicon technology and is widely used in it. It is necessary to understand, experimentally and theoretically, the mechanism of charge transport in a memristor based on silicon nitride in the initial, high-resistance, and low-resistance states to develop a resistive memory element. At present, there is currently no single universal model of charge transport in a memristor based on silicon nitride. In our work, the charge transport of the initial, high, and low resistive states in an SiNx-based memristor is analyzed with four bulk-limited charge transport models. It is established that the Frenkel model of Coulomb traps ionization, Hill-Adachi model of overlapping Coulomb traps, and Makram-Ebeid and Lannoo model of multiphonon isolated traps ionization, quantitatively, do not describe the charge transport of the SiNx-based memristor in any state. The Nasyrov-Gritsenko model of phonon-assisted tunneling between traps gives a consistent explanation of the charge transport of the SiNx-based memristor in all states at temperatures above room temperature.
Charge transport mechanism of high-resistive state in RRAM based on SiOx
(2019-01-21)
Gismatulin, A. A.
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Kruchinin, V. N.
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Gritsenko, V. A.
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Prosvirin, I. P.
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Yen, T. -J.
Nonstoichiometric silicon oxide SiOx is a promising material for developing a new generation of high-speed, reliable flash memory based on the resistive effect. It is necessary to understand the electron transport mechanism of the high-resistive state in SiOx to develop a resistive memory element. At present, it is generally accepted that the charge transport of the high-resistive state in the Resistive Random Access Memory (RRAM) is described by the Frenkel effect. In our work, the charge transport of the high-resistive state in RRAM based on SiOx is analyzed with two contact-limited and five volume-limited charge transport models. It is established that the Schottky effect model, thermally assisted tunneling, the Frenkel model of Coulomb trap ionization, the Makram-Ebeid and Lannoo model of multiphonon isolated trap ionization, and the Nasyrov-Gritsenko model of phonon-assisted tunneling between traps, quantitatively, do not describe the charge transport of the high-resistive state in the RRAM based on SiOx. The Shklovskii-Efros percolation model gives a consistent explanation for the charge transport of the highresistive state in the RRAM based on SiOx at temperatures above room temperature. Published under license by AIP Publishing.
Evolution of the conductivity type in germania by varying the stoichiometry
(2013-12-02)
Islamov, D. R.
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Gritsenko, V. A.
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Cheng, C. H.
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Chin, A.
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交大名義發表
Information regarding the conductivity type of Si/GeOx/Ni structures with various stoichiometry has been obtained using experiments on injection of minority carriers from n- and p-type silicon. Results show that non-stoichiometric GeOx films exhibit bipolar conductivity, that is, holes as well as electrons contribute to the charge transport. Stoichiometric GeO2 films exhibit unipolar electron conductivity. (C) 2013 AIP Publishing LLC.
Local Oscillations of Silicon-Silicon Bonds in Silicon Nitride
(2018-05-01)
Volodin, V. A.
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Gritsenko, V. A.
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Chin, A.
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交大名義發表
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National Chiao Tung University
Raman spectra of films of nearly stoichiometric amorphous silicon nitride (a-Si3N4) reveal a contribution due to local oscillations of silicon-silicon (Si-Si) bonds. This observation directly confirms that the almost stoichiometric a-Si3N4 contains Si-Si bonds, which, according to theoretical predictions, act as electron and hole traps that are responsible for the memory effect in Si3N4.
Mechanism of GeO2 resistive switching based on the multi-phonon assisted tunneling between traps
(2012-06-11)
Shaposhnikov, A. V.
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Perevalov, T. V.
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Gritsenko, V. A.
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Cheng, C. H.
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Chin, A.
Model of evenly distributed traps in bulk dielectric is proposed for the resistive memory switching mechanism. Switching from high resistance to the low resistance state is explained by several-fold increase in trap concentration after the application of switching voltage. Both high and low resistance conductivities are governed by multi-phonon ionization and tunneling between neighboring traps. Thermal trap energy for oxygen vacancy and electron effective mass for crystal alpha-GeO2 were calculated using density functional theory and used for the fitting of our charge transport model of resistive memory. The model was verified on the TaN-GeO2-Ni structure with good semi-quantitative agreement with experiment. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4729589]
Mechanism of stress induced leakage current in Si3N4
(2019-07-01)
Gritsenko, V. A.
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Gismatulin, A. A.
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Baraban, A. P.
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Chin, A.
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交大名義發表
In this paper, the experimental current density versus electric field characteristics of Si3N4 before and after the electrical field-induced stress were measured. It is shown that, the Frenkel model of Coulomb trap ionization, Hill-Adachi model of overlapping Coulomb traps, Makram-Ebeid and Lannoo multiphonon isolated trap ionization model do not describe the charge transport of Si3N4 before and after the electrical field-induced stress. The Nasyrov-Gritsenko model of phonon assisted tunneling between traps quantitatively describes the hole transport mechanism in Si3N4 before and after the induced stress at traps energies W-t = 1.6 eV and W-opt = 3.2 eV. The current leakage at different induced stresses in Si3N4 is explained by the increase of trap concentration via the creation of Si-Si bonds, which are traps in Si3N4.
Memristor effect in GeO[SiO2] and GeO[SiO] solid alloys films
(2019-06-10)
Volodin, V. A.
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Kamaev, G. N.
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Gritsenko, V. A.
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Gismatulin, A. A.
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Chin, A.
The p-Si(or n-Si)/GeO[SiO2] (or GeO[SiO])/indium-tin-oxide (ITO) structures were fabricated by simultaneous evaporation of GeO2 and SiO2 (or SiO) powders in high vacuum and further deposition of ITO contacts using the magnetron sputtering technique. The structural properties of the GeO[SiO2] and GeO[SiO] films were studied using FTIR and Raman spectroscopy. According to Raman data, the GeO[SiO] films deposited at a temperature of 100 degrees C contain amorphous Ge clusters. Their current-voltage characteristics were measured in the air atmosphere, and resistive switching (memristor effect) was observed in structures without a preliminary forming procedure. The Shklovskii-Efros percolation model gives a consistent explanation for the charge transport in the high-resistive state and the low-resistive state of memristors based on GeO[SiO2] or GeO[SiO] films.
Multiphonon trap ionization transport in nonstoichiometric SiNx
(2019-03-01)
Gritsenko, V. A.
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Gismatulin, A. A.
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Chin, A.
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交大名義發表
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National Chiao Tung University
It is generally accepted that the charge transport in dielectrics is governed by coulombic trap ionization due to a barrier lowering in high electric fields (Frenkel effect). In this paper, the charge transport mechanism in Si3N4 and nonstoichiometric silicon rich SiNx is experimentally studied and quantitatively analyzed with five theoretical models: Frenkel model of Coulomb traps ionization, Hill-Adachi model of overlapping Coulomb traps, Shklovskii-Efros percolation model, Makram-Ebeid and Lannoo model of multiphonon isolated traps ionization and Nasyrov-Gritsenko model of phonon-assisted electron tunneling between nearby traps. It is shown that the charge transport in Si3N4 and SiNx is qualitatively described by Frenkel effect, but Frenkel effect predicts an enormously low attempt to escape factor value. The charge transport at traps energies W-t = 1.6 eV and W-opt = 3.2 eV in Si3N4 and SiNx can be described by an increase in traps concentration in the framework of Makram-Ebeid and Lannoo model and Nasyrov-Gritsenko model. The Makram-Ebeid and Lannoo model quantitatively describes the charge transport in Si3N4 and SiNx with low silicon enrichment. The charge transport in nonstoichiometric SiNx with high silicon enrichment is well explained by Nasyrov-Gritsenko model.
Nanoscale potential fluctuation in non-stoichiometric HfOx and low resistive transport in RRAM
(2015-11-01)
Kruchinin, V. N.
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Aliev, V. Sh.
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PerevaIov, T. V.
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Islamov, D. R.
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Gritsenko, V. A.
We study the structure of non-stoichiometric HfOx films with variable composition using the methods of X-ray photoelectron spectroscopy and spectroscopic ellipsometry. HfOx, to a first approximation, is a mixture of HfO2 and Hf metal with a small amount (similar to 10-15%) of hafnium sub-oxides HfOy (y < 2). Spatial potential fluctuations, due to chemical compound fluctuations, lead to the percolation charge transport in such electronic systems. An application of these phenomena in resistive memory physics is discussed. (C) 2015 Elsevier B.V. All rights reserved.
Nanoscale potential fluctuations and electron percolation in silicon oxide (SiOx, x=1.4, 1.6)
(2019-09-01)
Gritsenko, V. A.
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Novikov, Yu N.
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Chin, A.
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交大名義發表
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National Chiao Tung University
Using the method of high-resolution x-ray photoelectron spectroscopy (XPS), the short order in the SiO1.4 film was studied. The random bonding (RB) and random mixture (RM) models do not describe the experimental spectra of SiO1.4. The intermediate model (IM) structure of SiO1.4, based on the local spatial fluctuations of the chemical composition, which leads to potential fluctuations for electrons and holes, is proposed. In a wide range of electric fields and temperatures, the current-voltage characteristics of SiOx films (x = 1.4, 1.6) were measured. The Efros-Shklovskii percolation theory was used for the description of SiOx conductance. The percolation energy values for electrons: 0.5 eV for SiO1.4 and 0.8 eV for SiO1.6 were obtained. Taking into account that the potential fluctuation amplitude for electrons is 2.6 eV, the spatial potential fluctuation estimates for them are 2.8 and 3.4 nm for x = 1.4 and 1.6, respectively.
Optical Properties of TiO2 Films Deposited by Reactive Electron Beam Sputtering
(2017-10-01)
Kruchinin, V. N.
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Perevalov, T. V.
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Atuchin, V. V.
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Gritsenko, V. A.
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Komonov, A. I.
Titanium dioxide (anatase, a-TiO2) films have been prepared by electron beam sputtering of a TiO2 target in reactive atmosphere and their structural, microstructural, and optical properties were evaluated by reflection high- energy electron diffraction (RHEED) and x-ray diffraction (XRD) analyses, atomic force microscopy (AFM), and spectroscopic ellipsometry (SE). Different reflection models for determination of film optical parameters were tested and compared. The dispersive optical parameters were defined using the Tauc-Lorentz model by SE in the photon energy range of E = 1.12-4.96 eV. The films were transparent at E < 3 eV, but noticeable absorption was detected at E > 3 eV. The bandgap was estimated at the level of E (g) ae 3.44 eV.
Origin of traps and charge transport mechanism in hafnia
(2014-12-01)
Islamov, D. R.
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Gritsenko, V. A.
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Cheng, C. H.
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Chin, A.
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交大名義發表
In this study, we demonstrated experimentally and theoretically that oxygen vacancies are responsible for the charge transport in HfO2. Basing on the model of phonon-assisted tunneling between traps, and assuming that the electron traps are oxygen vacancies, good quantitative agreement between the experimental and theoretical data of current-voltage characteristics was achieved. The thermal trap energy of 1.25 eV in HfO2 was determined based on the charge transport experiments. (C) 2014 AIP Publishing LLC.
Percolation conductivity in hafnium sub-oxides
(2014-12-29)
Islamov, D. R.
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Gritsenko, V. A.
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Cheng, C. H.
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Chin, A.
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交大名義發表
In this study, we demonstrated experimentally that formation of chains and islands of oxygen vacancies in hafnium sub-oxides (HfOx, x < 2) leads to percolation charge transport in such dielectrics. Basing on the model of Efros-Shklovskii percolation theory, good quantitative agreement between the experimental and theoretical data of current-voltage characteristics was achieved. Based on the percolation theory suggested model shows that hafnium sub-oxides consist of mixtures of metallic Hf nanoscale clusters of 1-2 nm distributed onto non-stoichiometric HfOx. It was shown that reported approach might describe low resistance state current-voltage characteristics of resistive memory elements based on HfOx. (C) 2014 AIP Publishing LLC.
Short-Range Order and Charge Transport in SiO (x) : Experiment and Numerical Simulation
(2018-06-01)
Gritsenko, V. A.
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Novikov, Yu. N.
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Chin, A.
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交大名義發表
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National Chiao Tung University
The structure of nonstoichiometric silicon oxide (SiO (x) ) has been studied by the methods of highresolution X-ray photoelectron spectroscopy and fundamental optical-absorption spectroscopy. The conductivity of SiO (x) (x = 1.4 and 1.6) films has been measured in a wide range of electric fields and temperatures. Experimental data are described in terms of the proposed SiO (x) structure model based on the concept of fluctuating chemical composition leading to nanoscale fluctuations in the electric potential. The maximum amplitude of potential fluctuations amounts to 2.6 eV for electrons and 3.8 eV for holes. In the framework of this model, the observed conductivity of SiO (x) is described by the Shklovskii-Efros theory of percolation in inhomogeneous media. The characteristic spatial scale of potential fluctuations in SiO (x) films is about 3 nm. The electron-percolation energy in SiO1.4 and SiO1.6 films is estimated to be 0.5 and 0.8 eV, respectively.