Generation Of New Defects Research Articles

Dual defect detection and generation system in planar surface

The main problem of applying neural networks in the task of defect detection is that there is a limitation in the size of the set of annotated defect images compared to the set of defect-free images. This imbalance in the dataset poses a challenge for the model to effectively learn and generalize patterns associated with defects. The scarcity of annotated defect samples hinders the model's ability to capture the diverse characteristics of anomalies, making it prone to misdetection and reduced performance on real-world data. To solve this problem, the authors have proposed a neural network architecture based on two neural networks U-Net++ and PatchCore trained in the student-teacher paradigm. In this paradigm, the student model undergoes initial training exclusively on defect-free images. Consequently, disparities emerge in the learned features between the student and teacher models, facilitating the computation of an anomaly metric and streamlining the anomaly localization process. The aim of the research is to improve the efficiency of defect detection by creating methods and algorithms, and dataset augmentation systems, as an option to solve the problem of defect-free images. The overarching goal of this research is to enhance the efficacy of defect detection through the development of methodologies, algorithms, and dataset augmentation systems. This serves as a strategic approach to address the inherent challenge posed by the scarcity of annotated defect images in comparison to their defect-free counterparts. By creating methods and augmenting datasets, we aim to mitigate the limitations imposed by the uneven distribution of defect and defect-free samples, ultimately advancing the robustness and performance of defect detection models. A dual system of defect detection based on the U-Net++ pre-trained network and feature estimation of individual fragments based on the PatchCore network is presented. The research incorporates computational experiments designed to assess the effectiveness of the proposed method in comparison to existing counterparts. An in-depth efficiency analysis has been conducted, focusing on dataset enrichment using the generative-adversarial network ResStyleGAN. This examination aims to provide empirical evidence of the method's performance and its potential advantages over established approaches in the context of defect detection. The method developed, centered around the dual system PatchNet++ and preliminary generation of new defects using ResStyleGAN, is positioned for practical application in real production scenarios. Subsequent stages involve a detailed analysis to evaluate its performance and suitability in real-world settings.

Effect of Temperature-Dependent Low Oxygen Partial Pressure Annealing on SiC MOS.

Oxygen post annealing is a promising method for improving the quality of the SiC metal oxide semiconductor (MOS) interface without the introduction of foreign atoms. In addition, a low oxygen partial pressure annealing atmosphere would prevent the additional oxidation of SiC, inhibiting the generation of new defects. This work focuses on the effect and mechanism of low oxygen partial pressure annealing at different temperatures (900-1250 °C) in the SiO2/SiC stack. N2 was used as a protective gas to achieve the low oxygen partial pressure annealing atmosphere. X-ray photoelectron spectroscopy (XPS) characterization was carried out to confirm that there are no N atoms at or near the interface. Based on the reduction in interface trap density (Dit) and border trap density (Nbt), low oxygen partial pressure annealing is proven to be an effective method in improving the interface quality. Vacuum annealing results and time of flight secondary ion mass spectrometry (ToF-SIMS) results reveal that the oxygen vacancy (V[O]) filling near the interface is the dominant annealing mechanism. The V[O] near the interface is filled more by O2 in the annealing atmosphere with the increase in temperature.

Investigation of Temperature Dependence of mmWave Power Amplifier Large-Signal Reliability Performance

This work aims to study the temperature dependence on the long-term reliability of a power amplifier (PA) cell fabricated using 40-nm partially depleted-silicon on insulator (PD-SOI) nFET under dc and large-signal RF stress. Voltage swing caused by large RF signals complicates the stress mechanism due to frequent switching of stress from conducting to nonconducting. The impact of temperature on the time slope exponent ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${n}$ </tex-math></inline-formula> ) is also analyzed to understand the degradation mechanism at different temperatures. The values of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${n}$ </tex-math></inline-formula> are found to increase with the temperature pointing to the generation of new defects at the interface. A comparative reliability analysis is presented for dc, small-, and large-signal performance under varied accelerated dc and large-signal stress at drain and gate for different temperatures. Unity gain frequencies are also temperature sensitive and show high degradation at elevated temperatures. In our study, we have investigated the lifetime as a function of temperature of the PA operating in compression. It is observed that the lifetime is more than ten years when the PA operates at room temperature, which deteriorates as the measurement chuck temperature rises.

Dynamical Models of Plasticity with Nonmonotonic Deformation Curves for Nanomaterials

Nanomaterials are widely used in different fields, such as microelectronics, industry, and nanocomposites, and they can exhibit unstable deformation behaviour depending on the strain rates. Under strain rates of 10−4–10−1 s−1, the deformation of nanomaterials, unlike the quasi-static deformation of micromaterials, is characterized by the presence of the rate sensitivity as a possible scale phenomenon in dynamic plasticity. In this paper, the relaxation model of plasticity for the prediction of deformation curves at different strain rates is used. It allows us to comprehensively study the effects of strain hardening in a wide range of deformation conditions for coarse-grained materials and nanomaterials. Considering the plastic deformation of the nanosized samples in the early stages, dynamical softening, associated with a generation of new defects, and dynamic hardening, are crucial. The proposed model, using one parameter or the classical hardening law as an example of nanosized gold whisker crystals, tungsten single-crystal pillars, and single-crystalline Au-Ag alloy nanowires, is verified. Calculated sets of parameters of characteristic time, as a parameter of rate sensitivity of a material, and hardening parameters for different nanomaterials are compared. It is shown that the characteristic relaxation times for the single-crystal nanomaterials (100–103 s) are greater than for the nanostructured materials (10−6–10−4 s). Despite the manifestation of dynamics at different strain rates of nanomaterials, single crystal and nanostructured materials, the proposed model can be successfully applied to materials with different degrees of hardening or softening.

INFLUENCE OF REPAIR ON THE BASIS OF THERMAL TREATMENT ON CORROSION RESISTANCE OF WELDED CONNECTIONS SECTIONS OF LONG-TERM MAIN PIPELINES

Background The main cause of accidents of long-term operation main pipelines operating in the Republic of Belarus is the failure of ring welded joints due to the development of existing ones and the generation of new defects that lead to pipeline rupture or the formation of a corrosion fistula. The restoration of the visco-plastic properties of the welded metal is possible due to the repair work using the heat treatment method. At the same time, there are no studies on the effect of this method on the corrosion resistance of welded joints. Aims and Objectives To determine the effect of heat treatment on the corrosion resistance of sections of the ring welded joint of long-term operation main pipelines. Methods Corrosion studies were carried in accordance with the recommendations of State Standard 9.908 «Unified system of corrosion and ageing protection. Metals and alloys. Methods for determination of corrosion and corrosion resistance indices», State Standard 9.907-83 «Unified system of corrosion and ageing protection. Metals, alloys, metallic coatings. Methods for removal of corrosion products after corrosion tests», State Standard 9.905-82 «Unified system of corrosion and ageing protection. Corrosion test methods. General requirements». Results The use of heat treatment for repair work leads not only to the restoration of the visco-plastic properties of the welded joints of the long-term operation main pipelines, but also to a decrease in the corrosion rate by an average of 4 %. An increase in corrosion resistance is observed in all areas of the welded joint, which can be explained by the relative homogenization of the microstructure and the removal of residual stresses.

Phase transformation and modifications in high-k ZrO2 nanocrystalline thin films by low energy Kr5+ ion beam irradiation

In present communication, zirconium oxide (ZrO2) thin films of thickness (155 nm) were grown by using RF sputtering technique. To address and systematically understand the effects of low energy (800 keV) irradiation, high-k ZrO2 thin films were irradiated at room temperature by Kr ions with a range of fluence 1E15 to 1E17 ions. cm−2. The polymorphous zirconia pristine and irradiated thin films were characterized through X-ray diffraction (XRD) technique which confirms the coexistence of monoclinic and tetragonal phases. Monoclinic to tetragonal structural phase transformation was observed for Kr5+ ions irradiated samples at a fluence of 5E15, 1E16, 1E17 ions. cm−2. All samples were characterized by UV–Vis spectroscopy to study the mechanism of variation in optical energy band gap (4.42–4.52 eV), Urbach energy (402–449 meV) and refractive index (1.518–1.523) with increasing ion fluence. Photoluminescence (PL) spectroscopy was done at room temperature to record the significant PL broad prominent emission peaks at 350 nm and 430 nm and the peak intensity of these peaks significantly varies due to the annihilation of primary defects or generation of new defects centres by the influence of Kr ion irradiation. To determine the significant variation in grain size (50–85 nm) and RMS surface roughness (0.54–1.04 nm), pristine and irradiated sample were characterized by atomic force microscopy (AFM). A complete mechanism of the evolution of surface roughness was analyzed by determining the power spectral density (PSD). Further surface roughness component in the range of 0.4–1.7 was calculated using the slope of the tail of PSD. The FTIR spectra of pristine and low energy ion irradiated ZrO2 thin films were recorded in the range of 1250–3200 cm−1. The Rutherford backscattering spectrometry (RBS) was carried out in channeling condition and the experimental results were simulated to evaluate the elemental composition of Zr and O (⁓1:2) and film thickness (155 nm) of the samples. The changes of the chemical binding energy of ZrO2 thin films of Zr 3d and O 1s region before and after ion irradiation were investigated by x-ray photoelectron spectroscopy (XPS).

Simulations of Correlative Defect Forming in Hafnia

High-κ hafnium oxide is widely used in different electronic devices. The electronic properties of HfO2 (e.g. leakage currents, optics) are defined by defects and traps, namely by oxygen vacancies (VO). Generation of new defects leads to breakdown, increasing the leakage, that leads to the FET and FRAM degradation. On the other hand, active layers in RRAM devices use traps as precursors for HRS/LRS switch. The aim of the work is predicting the defect forming in dielectrics in strong electric fields using analytical, numerical and ab initio simulations. Despite the advances in computational performance, the ab initio simulations still require large time and efforts. Analytical and half-analytical solutions of the problem can be helpful in a way of predicting conditions for defect formation.The rate of new defect generation in the hafnium oxide with only one VO was calculated using the heat transfer equation with a strong positive loopback. The analytical and half-analytical solutions were found and compared with numerical ones. The most probable positions of new defect at specific electric field were found. These results were compared with ab initio (DFT) calculations of oxygen polyvacancy structure in monoclinic HfO2. It was found that the most favorable spatial configuration of an oxygen polyvacancy is a chain, where the next vacancy is formed near the already existing one, and no more than 2 removed O atoms are related to a Hf atom. Found distances between neighboring VO are (4.05-4.21) Å.The work was supported by the Russian Science Foundation, grant #16-19-00002.

Statistical model and structural reliability analysis for onshore gas transmission pipelines

Abstract The reliability of gas pipelines against rupture can be estimated based on historical failure data and theory of structural reliability. In this study, an integrated model for reliability analysis of failure data is presented jointly with a robust structural reliability model for the purpose of comparison and cross-verification. The statistical model adopts a parametric hybrid empirical hazard model complemented with a robust data processing technique known as the nonlinear quantile regression for reliability analysis and prediction. This model provides inferences on the complete lifecycle reliability of the average pipe segment in the region under study. The structural reliability model is segment based and estimates rupture probabilities due to external metal loss corrosion. The non-homogeneous Poisson process is used to model the generation of new defects and the Poisson square wave process is used to model the growth of defects. The internal pressure load is modelled as a discrete Ferry-Borges stochastic process. Then, an inspection and maintenance plan is incorporated based on ASME B31.8S code of practice, for the service life considered. The probability of detection and measurement error of the inspection tools is also incorporated in the model. A numerical example of these models in an industrial context is presented. Onshore gas transmission pipeline rupture data for the period from 2002 to 2014, was obtained from the United States Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) database and analysed. The comparative study of the proposed methodologies can assist gas pipeline operators in the informed implementation of optimal maintenance strategies based on risk prioritization.

Creep behavior of nanocrystalline Au films as a function of temperature

Freestanding nanocrystalline Au films, subjected to nominally elastic loads at 25–110 °C, demonstrated high primary (10−7–10−4 s−1) and steady-state creep rates (10−8–10−5 s−1). The deformation mechanisms for creep were strongly temperature dependent: grain boundary sliding-based creep dominated at room temperature and 50 °C, while the contribution of dislocation-mediated creep increased at 80 and 110 °C. The effect of applied stress on primary and steady-state creep strain at different temperatures was captured well by a non-linear model that was based on the kinetics of thermal activation. Multi-cycle creep experiments showed that at room temperature virtually all the primary strain accumulated during each forward creep cycle was recovered upon complete unloading. As the contribution of dislocation-mediated creep increased with temperature, the ratio of strain recovery to primary strain accumulated during each cycle was reduced due to the accumulation of plastic strain at higher temperatures. Notably, at all temperatures, the steady-state creep rate decreased after the first creep cycle. Moreover, the entire creep response remained virtually unchanged in all subsequent cycles, which implies that the first creep cycle resulted in mechanical annealing. This conclusion was further supported by calculations of the activation entropy: A reduction in its magnitude between the first and all subsequent creep cycles at all temperatures pointed out to mechanical annealing of initial material defects during the first loading cycle. The negative values of the calculated activation entropy indicated that entropy changes due to annihilation of defects-dominated entropy changes associated with the generation of new defects. Finally, the activation entropy for steady-state creep was temperature insensitive, but increased with stress, which is consistent with an increase in defect generation at higher stresses.

Positron annihilation studies of high-manganese steel deformed by rolling

Abstract Positron annihilation spectroscopy (PAS) has been used to study the annealing behavior of cold rolled Fe – 21 wt% Mn steel with 0.05 wt% C. After the initial annealing of defects shown by Doppler broadening of the annihilation line, a slight increase in the annihilation line shape parameter, i.e., the so-called S parameter and then its decrease in the temperature range between 225°C and 450°C indicates generation of new defects and their subsequent annealing. This temperature range coincides with X-ray diffraction measurements, which indicate reversion of deformation-induced ε-martensite. However, for annealing in this temperature range with slow cooling of the sample, the formation of ferrite already starts. The results are compared with our previous results for deformed austenitic stainless steel 1.4301 (EN) where only reversion of deformation-induced α′-martensite was detected.

The effect of the thermal reduction temperature on the structure and sorption capacity of reduced graphene oxide materials

The influence of reduction temperatures on the structure and the sorption capacity of thermally reduced graphene (TRGO) has been investigated systematically. A set of TRGO materials were prepared by thermal treatment of parent graphene oxide (GO) at five temperatures (T=200, 300, 500, 700, and 900°C). Investigations of these materials by X-ray diffraction, Raman spectroscopy and X-ray photoemission spectroscopy methods have shown that both the structure and the residual oxygen functional groups on the TRGO surface can be controlled by varying the temperature of the thermal treatment. The data on the sorption and desorption of 4He, H2, N2, Ne and Kr gases in the temperature interval T=2–290K clearly demonstrate that the sorption capacity of TRGO is closely related to the structural changes induced by the treatment temperatures. It is important that the sorption capacities of TRGOs treated at 300°C and at 900°C significantly increase for all the gases used. The prominent increase in the sorption capacity at 300°C is attributed to the structural disorder and liberation of the pores caused by the removal of intercalated water and labile oxygen functional groups (oFGs) favored at this temperature. At 900°C the sorption capacity increases due to the generation of new defects on the TRGO surface, which provide additional access to the internal space between the folds and sheets of the TRGO structure. By tailoring the structural properties we emphasize the potential of TRGO as a highly efficient sorbent.

In‐Situ Reactor Radiation‐Induced Attenuation in Sapphire Optical Fibers

The purpose of this work was to determine the suitability of using instrumentation utilizing sapphire optical fibers in a nuclear reactor environment. In this work, the broadband (500–2200 nm, or 0.56–2.48 eV) optical transmission in commercially available sapphire optical fibers was monitored in‐situ prior to and during reactor irradiation. The sapphire fibers were irradiated at a neutron flux of 1.5 × 1012 n/(cm2·s) and a gamma dose rate of 75 kGy/h (dose in sapphire) to a total neutron fluence of 1.1 × 1017 n/cm2 and total gamma dose of on the order of 1.5 MGy. Consistent with previous gamma irradiation experiments, an absorption band centered below 500 nm (the minimum measurable wavelength using the measurement system described in this work) and extending as far as ~1000 nm reached saturation during irradiation in the gamma shut‐down field (the gamma‐ray radiation field that is present in the reactor post‐operation, as a consequence of the decay of radioisotopes that were produced during reactor operation) of the reactor prior to reactor irradiation. Beginning reactor irradiation and increasing the reactor power caused rapid increases in attenuation, followed by a linear increase with irradiation time at constant reactor power. Shutting down the reactor caused a decrease in the added attenuation; however, restarting the reactor caused the added attenuation to rapidly return to values almost identical to those observed at the end of the previous irradiation. The decrease in attenuation that was observed after the reactor was shut down shows the importance of the in‐situ nature of the measurements made in this work (previous ex‐situ attenuation measurements could not have captured this effect). A model is proposed for the experimentally obtained values of the radiation‐induced attenuation that involves three previously identified color centers including a composite V‐center, a center, and a center. The model accounts for gamma radiation‐induced ionization of pre‐existing defects, generation of new defects via displacement damage, and conversion between defect centers via ionization and charge recombination.

Cost-based optimal maintenance decisions for corroding natural gas pipelines based on stochastic degradation models

This paper investigates the optimal inspection interval for newly-built onshore underground natural gas pipelines with respect to external metal-loss corrosion by considering the generation of corrosion defects over time and time-dependent growth of individual defects. The non-homogeneous Poisson process is used to model the generation of new defects and the homogeneous gamma process is used to model the growth of individual defects. A realistic maintenance strategy that is consistent with the industry practice and accounts for the probability of detection (PoD) and sizing errors of the inspection tool is incorporated in the investigation. Both the direct and indirect costs of failure are considered. A simulation-based approach is developed to numerically evaluate the expected cost rate at a given inspection interval. The minimum expected cost rule is employed to determine the optimal inspection interval. An example gas pipeline is used to examine the impact of the cost of failure, PoD, the excavation and repair criteria, the growth rate of the defect depth, the instantaneous generation rate of the generation model and defect generation model on the optimal inspection interval through parametric analyses. The results of the investigation will assist engineers in making the optimal maintenance decision for corroding natural gas pipelines and facilitate the reliability-based corrosion management.

(Invited) Replacement Metal Gate/High-k Last Technology for Aggressively Scaled Planar and FinFET-Based Devices

For (sub-)22nm nodes, new device architectures such as multi-gate FinFET-based devices have long been regarded an attractive option to allow further CMOS scaling thanks to their improved electrostatics and reduced VT-variability [1]. In this work, we address the need for processes compatible with their 3D-architecture by reporting on a novel EWF engineering approach [2] which enables wide VT-modulation (>500mV ΔVT in narrow fin (WFin≥5nm), triple-gate FinFETs in Fig. 1), with no EOT nor JG penalty, improved mobility and BTI, excellent mismatch performance, up to ~6.3× reduced noise (Fig. 2), and minimized parasitic Rgate and σ(Rgate), while suitable also for scaled planar FETs where larger EWF shifts from mid-gap to reach low or high-VT targets are needed. It relies on diffusion mechanisms in the gate stack, namely controlled Al diffusion from the fill-metal (CoxAly) through an ultra-thin TaN layer into the TiN covering the high-k dielectric (e.g., HfO2), and fine-tuned TiN/TaN thicknesses. Since Al-rich TiN has a more n-type EWF, stacks with higher amount of Al diffused into TiN translate into lower EWF values (→ lower NMOS VT), with TiN growth optimized for enhanced (NMOS) or inhibited (PMOS) Al diffusion into/through it.Focusing next on gate dielectric scaling, we report a thorough evaluation of the impact of HfO2 doping [3], post high-k deposition thermal (PDA) and SF6-based plasma treatments [4,5] for planar vs. FinFET devices with different Si crystal orientations for the fin top and sidewall surfaces, providing a deeper insight into underlying degradation mechanisms. Higher k-value HfO2 (k~30) is achieved by introducing a metallic dopant during HfO2 growth, followed by an 800°C PDA which crystallizes HfO2 into its cubic phase. Up to 103× JG reduction at ~9.7Å EOT and net performance (ION) and reliability (BTI, TDDB) improvements when normalized to JG make this material attractive for low-power applications. F incorporation into the gate stack through exposure of HfO2 to a SF6-plasma results in substantially reduced Nit and noise values, improved mobility, and no EOT penalty down to narrow fin devices (WFin≥5nm), mitigating the impact of fin patterning, fin corners and fin sidewalls crystal orientations due to defects passivation by Hf-F and Si-F bonds formation. The plasma was optimized by increasing the number of ions reaching the bottom of narrow, high aspect-ratio gate trenches such that it can be used to incorporate F in the gate stack and to selectively remove the p-EWF/barrier metals (TiN/TaN) from NMOS areas in a simplified, highly scalable dual-EWF metal CMOS scheme [5] suitable for 2D and 3D device architectures and which maximizes the space for gate metallization. NBTI lifetime improvement with SF6 at 125°C is however fairly modest in the (sub-)1nm EOT regime, substantially increasing upon PDA introduction in the process flow, and for higher PDA temperatures (760°C→800°C). PDA devices exhibit reduced JG (enabling nFETs with ~10× lower JG at given VT) and show considerably smaller total effective trap density values, despite an increase in Nit (~1.4-1.8×), thanks to reduced bulk traps/defects. The latter seem thus to play a key and dominant role in NBTI for ultra-thin EOT, being mostly pre-existing defects contributing to charge trapping and de-trapping during stress and relaxation as inferred by the larger recoverable (R) vs. permanent BTI degradation components, calculated assuming universality of relaxation. Less steep R vs.stress time dependence in PDA devices also indicate less generation of new defects during stress, with improved hot-carrier immunity due to less charge trapping into bulk defects corroborating reduced presence of the latter. Further reliability gain is obtained for PMOS with (100) fin sidewalls in agreement with LF-noise results (Fig. 2).

The Annealing Behavior of the Subsurface Zone Induced by Friction in Bismuth Detected by Positron Lifetime Technique

The annealing behavior of the subsurface zone (SZ) in pure bismuth induced by dry sliding was studied using the positron lifetime measurement. This measurement allows us to detect the SZ and its recovery, and recrystallization processes. The comparative measurements of the sample exposed to compression revealed the thermal stability of the SZ. The compressed sample rebuilt its structure due to the recovery and recrystallization processes at the temperature of 60 °C, whereas the sample exposed to dry sliding does it at higher temperature of 260 °C, which is close to the melting point. The isothermal annealing at the temperature of 100 °C confirmed these results. The defect depth profile induced by dry sliding evolves with the annealing temperature in such a way that the concentration of defects at the worn surface gradually decreases, but at the depth between 50 and 170 μm, the generation of new defects takes place at the temperature of 75, 100 and even at 175 °C. At the temperature of 175 °C, the defects still are extended up to the depth of about 60 μm from the worn surface. The results were qualitatively confirmed by the measurements of the Vickers microhardness depth profile. Similar annealing behavior of the SZ was observed in pure magnesium.

Generation/recovery mechanism of defects responsible for the permanent component in negative bias temperature instability

The defects responsible for the permanent component observed in negative bias temperature (NBT) stressed metal-oxide-semiconductor field effect transistors with an oxynitride gate insulator were investigated by using isochronal annealing experiments, spin dependent recombination (SDR), and spin dependent tunneling (SDT) technique. Two defects were found in the permanent component after light NBT stresses; interface states (Dit) and fixed positive charges (Dpc), which are closely related. The data support a model where hydrogen emitted from interfacial Si-H bonds by NBT stresses reacts with Si-X-Si structures (X = oxygen or nitrogen) in the gate insulator, which leaves silicon dangling bonds (Dit) and leads to the generation of Si-X+H-Si (overcoordinated oxygen or nitrogen, Dpc). Heavy NBT stresses simultaneously accelerate the formation and generation of new defects, which act as additional Dit and Dpc. Moreover, these defects cause stress-induced leakage current. Concerning their origin, defects similar to K- and E′γ-centers were detected by using SDR and SDT. They are unrelated to hydrogen and can be formed through the breaking of Si-X bonds. On the basis of these results, we propose a model for the generation and recovery behavior of defects and present a comparison with the previous studies.

Positron annihilation studies of recrystallization in the subsurface zone induced by friction in magnesium—effect of the inhomogeneity on measured positron annihilation characteristics

The discussion of the positron annihilation studies of crystal structure defects, like vacancies, dislocations, grain boundaries and the defect depth profile, is presented. The role of the positron implantation depth and positron diffusion in such studies has been considered in detail. For description of the measured annihilation characteristics the proposed theoretical models take into account both effects. The annealing studies of defects created in pure magnesium by compression or dry sliding-wear were used for demonstration of the discussed thesis. The positron lifetime measurements were applied for monitoring open volume defects behavior. It was demonstrated that annealing at the temperature of about 300 °C removes the defects created by compression. Application of the proposed model to description of the data obtained allows to determine the activation energy of the grain boundary mobility in pure magnesium equal to Q=0.56±0.18 eV. However, defects created by the dry sliding are not completely annealed up to the temperature of 500 °C. The defect depth profile induced by dry sliding evolves with the annealing temperature in such a way that at the worn surface concentration of defects gradually decreases but at the depth between 60 and 100 μm the generation of new defects takes place at temperature of 150 and 225 °C. Above 300 °C the defects still are extended up to the depth of about 80 μm.

Charge trapping analysis of Al2O3 films deposited by atomic layer deposition using H2O or O3 as oxidant

In this work, the authors focus on the charge trapping behavior of Al2O3 layers deposited by atomic layer deposition. The goal is to give an insight into the effects of the oxidant source (H2O or O3) and the postdeposition anneal on the charging phenomena and the generation of new defects during electrical stress. For this purpose, current–voltage, capacitance–voltage, and conductance–voltage characteristics of Al/Al2O3/p-Si capacitors are analyzed before and after constant voltage stress and several phenomena such as the generation of neutral traps in the bulk dielectric, slow states, interface states, and charge trapping related degradation during the electrical stress are investigated. Finally, the impact of the oxidant source on the Al2O3 layer reliability is discussed.

RESTRUCTURING DEFECT SURFACE-BARRIER STRUCTURES Bi-Si-Al STIMULATED ACTION RADIATION

In this work the surface-barrier structures based on p-Si with different resistivity (ρ1 =24 Ohm∙sm, ρ2 = 10 Ohm∙sm) were made and their electrophysical characteristics were investigated under the influence of X-rays. It is shown that depending on the defect structure of silicon substrate, the action of irradiation leads to generation of new defects or changing of charge state of existing defects. Consequently, the mechanism of current transfer in irradiated structures changes.

AFM study of the microwave effect on hydrogen-containing ferroelectric triglycine sulfate

Nanoscale supramolecular structures and their transformations under exposure to microwaves in hydrogen-containing ferroelectric, i.e., triglycine sulfate (TGS), were studied by atomic-force microscopy. It was shown that prolonged (2–5 h) irradiation of TGS crystal at a frequency of 40 GHz results in changes in the cleavage surface, which can be interpreted as radiation-induced “annealing” of the crystal with simultaneous generation of new defects. An exposure mechanism based on the effects of commensurability of the time of flight of quasifree dipole particles (protons) with the high-frequency field’s period is proposed.