Yu. V. Markin

Distribution of mobile ions in thin insulator films at the insulator-semiconductor interface

The influence of a semiconductor on the mobile ion distribution in insulator thin films at the insulator-semiconductor interface was considered. The degree of ion localization at the interface under the field effect in the film was calculated. The threshold of the ion delocalization with a decrease in the voltage applied to the structure was determined. The relation between the delocalization thresholds and ion current peaks in dynamic current-voltage characteristics of the system is discussed.

Macroscopic ion traps at the silicon-oxide interface

The drift kinetics of the mobile charge in SiO2 films, its capture on ion traps localized at the Si-SiO2 interface, and ion emission from these traps are investigated by measuring the capacitance-voltage characteristics, the dynamic current-voltage characteristics, and the thermally stimulated depolarization current of the insulator. The current components (peaks) associated with the emission of particles trapped on the interface during thermofield treatment are isolated in an explicit form. The charge of the surface ions is shown to be neutralized mainly by Si electrons, and the field dependence of the ion emission currents is characterized by an anomalous Schottky effect associated with opening of the ion-trap potential by the external field. The relationship between these traps and the potential inhomogeneities, i.e., potential wells for mobile particles, on the interface under consideration is discussed. It is noted that the mobile ions in the insulator can be used for interface potential inhomogeneity diagnostics.

Sodium-peak splitting in dynamic current-voltage characteristics of convective ion currents in metal-oxide-semiconductor structures

The results of simultaneous measurements of dynamic current-voltage and capacitance-voltage characteristics are presented for metal-oxide-semiconductor structures in the temperature range T = 420–470 K and voltage-sweep rates βv = 0.5–1000 mV/s. The convective currents Icon (V) in oxide are extracted from usual ion currents in the I-V characteristics. In Icon (V) curves, the Na+-ion peaks are split. In addition, an envelope curve is seen in initial portions of “fast” Icon(V) curves with βV ≳ 10 mV/s that indicates to the presence of a certain quasi-steady ion-transport mode. A more equilibrium mode at slow rates βV < 1 mV/s manifests itself in the form of stabilization of convective-current peak shapes. The nature of efficient neutralization of the second peaks in the Icon(V) dependences is discussed.

Manifestations of the deneutralization of mobile charges in SiO2 in the spectroscopy of the silicon-oxide interface

The total number of mobile ions in the oxide film in a Si-based MOS structure is determined by the conventional methods of recording capacitance-voltage and dynamic current-voltage characteristics. The fraction of ions in the neutral state at the Si-SiO2 interface is determined. Spectroscopy of the interface reveals a peak of the effective density of interface states. It is shown that the number of states in this peak corresponds to the number of neutralized particles. The mechanism for neutralization of the mobile charge of ions is discussed.

Segregation of mobile ions on insulator-semiconductor interfaces in metal-insulator-semiconductor structures

The equilibrium distribution of mobile ions was considered in metal-insulator-semiconductor (MIS) structures with ionic surface states at the insulator-semiconductor interface. The quasi-steady currentvoltage characteristics were calculated for ion currents in MIS structures. The population of surface states by ions was described by the Gibbs distribution.

Quasi-static ion currents in thin insulating films of metal-insulator-semiconductor structures and the distribution of ions in the films

A method for calculating the quasi-static current-voltage characteristics for ion currents in a metal-insulator-semiconductor structure is suggested. Theoretical and experimental peaks of ion currents in the current-voltage characteristic were compared. The influence of a semiconductor on the characteristic current-voltage shape was considered. The distribution of ions in the insulator film was calculated. Formulas for determining both the background concentration of ions in thefilm and their concentration at the insulator-semiconductor interface are suggested.

Determination of a Mobile-Ion Concentration in the Dielectric Films of Metal–Insulator–Semiconductor Structures

An experimental technique for determining the surface concentration NSof mobile ions in dielectric films of metal–insulator–semiconductor (MIS) structures is described. The technique is based on synchronous recording of the dynamic volt–ampere and low-frequency capacity–voltage characteristics of a sample under investigation. These experimental dependences are shown to ensure accurate extraction of the ion current peaks whose areas are proportional to NS. These characteristics also allow the relaxation of the surface semiconductor potential to be found, which is needed for reconstructing the dependence of the convection ion current on the voltage drop across the insulation gap of the MIS capacitor. A comparative analysis with other known methods for determining NSis carried out. The proposed technique helps find a mobile-ion concentration from a ∼ 5 × 109to 1013-cm–2range, including the case when ion current peaks do not appear on the current–voltage characteristics.

Phase Separation in GaMnAs Layers Grown by Laser Pulsed Deposition

GaMnAs layers grown by pulsed laser deposition were studied by magneto-optical transversal Kerr effect spectroscopy, spectral ellipsometry, resistivity and the Hall effect measurements, and magnetometry. The growth regimes for magnetically inhomogeneous layers containing Mn-enriched ferromagnetic regions with different composition and sizes were established. The layers grown at a temperature of 300°C exhibit a ferromagnetic behavior at temperatures below 80 K, which is conditioned by the presence of local ferromagnetic (Ga,Mn)As regions in the paramagnetic matrix. The nature of peculiarities in the TKE spectrum of these layers is discussed.

Data representation model for in-depth analysis of network traffic

This paper proposes a new object model of data for the in-depth analysis of network traffic. In contrast to the model used by most modern network analyzers (for example, Wireshark and Snort), the proposed model supports data stream reassembling with subsequent parsing. The model also provides a convenient universal mechanism for binding parsers, thus making it possible to develop completely independent parsers. Moreover, the proposed model allows processing modified—compressed or encrypted—data. This model forms the basis of the infrastructure for the in-depth analysis of network traffic.

Methods and software tools to support combined binary code analysis

Methods and tools for binary code analysis developed in the Institute of System Programming, Russian Academy of Sciences, and their applications in algorithm and data format recovery are considered. The executable code of various general-purpose CPU architectures is analyzed. The analysis is performed given no source codes, debugging information, and specific OS version requirements. The approach implies collecting a detailed machine instruction level execution trace; a method for successively increasing presentation level; extraction of algorithm’s code followed by structuring of both code and data formats it processes. Important results are obtained, viz. an intermediate representation is developed that allows carrying out most preliminary processing tasks and algorithm code extraction without having to focus on specifics of a given machine; and a method and software tool are developed for automated recovery of network message and file formats. The tools are integrated into the unified analysis platform that supports their combined use. The architecture behind the platform is also described. Examples of its application to real programs are given.