High-κ related reliability issues in advanced non-volatile memories

In the last decade, important technology solutions have been proposed to scale down Flash memory devices beyond the 30 nm node. The most important innovations are the introduction of charge trapping layer and high-κ materials in both bottom and top dielectric stacks. Such innovations allow reducing both the bottom dielectric thickness and the Program/Erase (P/E) voltages, while maintaining the P/E performances without degrading (theoretically) the memory device reliability. Theoretical advantages and reliability issues of these important innovations will be reviewed by addressing physical mechanisms responsible of reliability degradation. In particular, the reliability consequences of the discrete charge storage and of the high-κ band-gap engineered barriers bottom and top dielectric stacks will be carefully analyzed, relating high-κ material properties to memory device performances and reliability.     

Advanced thermal failure analysis and reliability investigations – Industrial demands and related limitations

The thermal interaction between actively operated integrated circuits and applied characterization tools is one of the most important ones within failure analysis (FA) and reliability/methodology (RM) investigations. Hereby different kind of thermal interaction mechanisms can be utilized, whereas these mechanisms have to be separated for instance into classes with respect to thermal excitation and/or detection, spatial limitations, and underlying physical principle. Although they all have in common the capability to link the thermo-electric device characteristic to a representing output signal, they have to be interpreted in completely different ways. Therefore, within this paper we discuss from a practical engineering point of view established FA/RM characterization techniques by means of infrared-lock in thermography (IR-LIT) and thermal induced voltage alteration (TIVA) case studies as well as the capability of non established ones like scanning thermal microscopy (SThM), thermal reflectance microscopy (TRM), and time domain thermal reflectance (TDTR). Hereby we focus on the complementarities of the methods for localization and characterization as well as on the according industrial demands and related limitations.     

Electro--Optical and Acousto--Optical Bistable Devices

Recently there has been a considerable interest in theoretical investigation of opticalbistability and practical applications of this phenomenon.This paper is devoted to inves-tigation of optical bistability in opto-electronical devices created by means of two me-thods.Bistability is achieved due to non-linearity of electro-optical and acousto-optical     

CSA-doped PANI/TiO2 hybrid BHJ solar cells – Material synthesize and device fabrication

In this study, camphorsulfonic acid (CSA) doped polyaniline (PANI) synthesized by oxidative polymerization and titanium-di-oxide (TiO₂) nanoparticles synthesized by sol-gel were solution blend in a mixed solvent of 1:1 m-cresol and chloroform to fabricate hybrid bulk heterojunction (BHJ) solar cells of structure ITO/PEDOT:PSS/CSA-doped PANI-TiO₂/Al. The effect of TiO₂ weight ratio on the cell performance was investigated by analyzing the structural and optical properties of CSA-doped PANI/TiO₂ hybrid thin films with different TiO₂ ratio. Crystalline structure of TiO₂ nanoparticles, polymer and hybrid thin films were identified by XRD studies and root-like structure of both polymer and hybrid thin films by SEM image. CSA-doped PANI was confirmed as p-type semiconductor through Hall-effect analysis. High absorption coefficient along with PL quenching in hybrid thin film confirms its application in solar cells as photoactive layer. For optimal fabrication conditions, maximum photo conversion efficiency (PCE) of 0.21% was obtained for a device with lower TiO₂ weight ratio. The results show that optimization of absorption intensity of CSA-doped PANI in the visible region of spectrum and morphology of hybrid films will effectively enhance the performance of hybrid solar cells. Error analysis of PCE for all the fabricated solar cells has been reported.     

Acousto-optic Devices: Theory and Applications

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Fibre to the home – infrastructure deployment issues

To date the use of optical fibre in the access network has typically only proved cost effective for supplying the high-bandwidthdemands of large corporate companies. For new and established network operators, however, the increasing demand forbandwidth to deliver bearer, interactive and bundled services to business and residential customers is requiring them to seriouslyconsider the high volume roll-out of optical-fibre-based systems. Network operators therefore face some major decisions, notonly in terms of the type of fibre transmission systems to deploy, but also on how to install a cost-effective network of fibrecables, ducting and joints to connect to the customers they wish to serve. Installing fibre in the ground represents a majorcommitment and a long term investment. Network operators can typically expected the fibre infrastructure to equate to at least60% of the cost of the overall access transmission system. Planning and building such networks involves major investment at theoutset, and, in todays highly competitive markets, operators are faced with the added complications of uncertain take-up ofservices by customers and the likelihood of high customer churn.This paper focuses on fibre to the home (FTTH) and the deployment options and challenges for the physical fibre infrastructure.The key difference associated with connecting optical fibre to residential properties instead of business properties is not technicalbut commercial. There is typically a much smaller potential revenue from a residential property than from a business property.This leads to a need for cost optimisation of both the transmission system and the fibre infrastructure. This paper examines thefibre infrastructure issues that need to be considered for an FTTH deployment and describes the fibre access network modellingactivities carried out by BTexact's Broadband Network Engineering unit. The aim of this modelling is both to automate theplanning of, and to optimise the costs of deploying, access networks based on real geographical and demographic data.     

Status and Trends in Advanced SOI Devices and Materials

提供了一种用于安德鲁反射测量样品制备新方法.该方法采用聚焦粒子束刻蚀和磁控溅射,可以获得可控的、干净的、无应力的纳米接触用于自旋极化探测.所制备的样品中,磁性和非磁性材料样品的反射谱都表现出复杂的峰和谷结构,这些结构可能源于与界面相关的零偏压反常以及与激发态相关的准离子相互作用.对另一个Co40Fe40B20合金样品采用简单的钕针尖压针方法进行了对比性测量,反射谱中没有观察到谷结构,但谱结构出现较明显的热扩展,这种热扩展可能来源于界面处的非弹性输运.所有的反射谱目前还不能由现有的理论给出令人满意的解释.利用点接触反射方法获得可靠的自旋极化信息还有赖于接触界面特征的进一步分析.而一个更切合实际的、更完善的理论成为迫切的需要.     

Sol–gel fabrication and enhanced optical properties,photocatalysis, and surface wettability of nanostructured titanium dioxide films

TiO₂ photocatalytic film, annealed at temperatures of 500 °C and 700 °C, was prepared on SiO₂ pre-coated glass via sol–gel technique for photocatalytic purposes and effects of catalyst-type on its properties were investigated by an X-ray diffractometer (XRD), Scanning Electron Microscope, UV–vis spectrophotometer, and contact angle measurements. The XRD results showed that present phases depend upon catalyst used in the solution and phase transformation behaves in a temperature-dependent manner. For the layers derived from sols containing acidic catalysts, the anatase structure dominated and exhibited much better photocatalytic activity. The results indicated that the sample derived from sol comprises H₂SO₄ as catalyst, and exhibits anatase grains with the lowest size. This could be the reason for its better photocatalytic activity. Finally, samples derived from sol containing acidic catalysts showed superhydrophilicity and superior cleaning ability.     

Acousto—optic Devices：Theory and Application

The basics and applications of acousto-optic devices are described,The applications include acousto-optic spectrum analyzer,acousto-optic deflector,acousto-optic processors and acousto-optic digital matrix computer.     

Design and fabrication of 2.4 GHz pre-biased rectifier

A 2.4 GHz rectifier operating in a region of low RF input power was developed. The rectifier has a cross-coupled bridge configuration and is driven by a differential RF input signal. Since a rectifier needs an RF signal higher than the threshold voltage of transistors, we introduced a pre-biasing circuit to compensate for the threshold voltage. A low-voltage digital circuit, subthreshold voltage regulator, and low-power level shifter were introduced for reducing the power consumption of the pre-biasing circuit and increasing the driving voltage for the switches at the same time. The circuit simulations revealed that the pre-biasing circuit was effective in a low RF input power region. However, the output voltage was degraded in a high power region. Then, we combined the pre-biased rectifier in parallel with a non-biased rectifier. Three types of rectifiers consisting of LC matching circuits, three-stage rectifier cells, and biasing circuits were designed and fabricated using a 0.18-μm mixed signal/RF CMOS process with one poly and six metal layers. The fabricated pre-biased rectifier operated in a region of RF input power of less than ?15 dBm, while the non-biased rectifier could not operate in this region. The parallel combination of pre-biased and non-biased rectifiers effectively solved the drawback of the pre-biased rectifier in a high RF input power region.     

Properties and Applications of Varistor–Transistor Hybrid Devices

The nonlinear current–voltage characteristics of a varistor device are modified with the help of external agents, resulting in tuned varistor–transistor hybrid devices with multiple applications. The substrate used to produce these hybrid devices belongs to the modified iron titanate family with chemical formula 0.55FeTiO₃·0.45Fe₂O₃ (IHC45), which is a prominent member of the ilmenite–hematite solid-solution series. It is a wide-bandgap magnetic oxide semiconductor. Electrical resistivity and Seebeck coefficient measurements from room temperature to about 700°C confirm that it retains its p-type nature for the entire temperature range. The direct-current (DC) and alternating-current (AC) properties of these hybrid devices are discussed and their applications identified. It is shown here that such varistor embedded ceramic transistors with many interesting properties and applications can be mass produced using incredibly simple structures. The tuned varistors by themselves can be used for current amplification and band-pass filters. The transistors on the other hand could be used to produce sensors, voltage-controlled current sources, current-controlled voltage sources, signal amplifiers, and low-band-pass filters. We believe that these devices could be suitable for a number of applications in consumer and defense electronics, high-temperature and space electronics, bioelectronics, and possibly also for electronics specific to handheld devices.     

Recombination Efficiency and Width in Bilayer Organic Light-emitting Devices

A bilayer model with ohmic anode contact and injection limited cathode contact has been proposed to calculate the recombination efficiency and recombination zone width of the device. The effects of the thickness of hole transport layer and the barriers of organic/organic interface on the combination efficiency and recombination width have been discussed. It is found that： （1） When the electrons are blocked fully and the holes are not blocked significantly at the organic/organic interface, for a given Lh/L, the recombination efficiency increases with increasing the applied voltage, but at a higher applied voltage, the recombination efficiency decreases with increasing Lh/L; （2） The recombination efficiency increases with increasing applied voltage and Hh＇, and when applied voltage and Hh＇ exceed some value, the recombination efficiency appears as a plateau; （3） The recombination width decreases with increasing the applied voltage and Lh/L. This model might explain the relative experiment phenomena.     

Cellulose Gel Mechanoreceptors – Principles,Applications and Prospects

In order to effectively harness varieties of mechanical waves or vibrations for the purpose of monitoring and/or powering, developments in responsive materials and conversion technologies are taking place driven by the world's current and future demands. One of the most popular novelties of the last two decades is represented by hydrogel- or ionogel-based flexible iontronics which constitute a wide family of innovative smart (self-powered) mechanoreceptors relevant for various applications such as personal health care, identity and safety monitoring, intelligent human-machine operation interfaces, underwater listening and communication, and so on. Cellulosic gels (CGs), as a promising green substitute for fossil fuel-derived materials, are extensively studied due to the possibility to choose between different cellulose types and to formulate networks chemically or physically, according to the adaptability requirements for each target application. The aim of this review is to showcase the cellulose structural versatility and to provide a summary of the principles during the formulation of CGs used for mechanosensing and mechanical energy scavenging, as well as their practical applications. Such an outlook of current challenges and overall prospects will serve as a stimulus for research on CG-based mechanoreceptors in the future.     

Development of 28?GHz and 77?GHz, Mega-Watt Gyrotrons for Fusion Devices

A 28 GHz 1 MW with TE_8,3 cavity for GAMMA10 tandem mirror and a 77 GHz 1.5 MW gyrotron with TE_18,6 for Large Helical Device (LHD) have been developed to upgrade their Electron Cyclotron Heating (ECH) systems. In the 28 GHz gyrotron, the maximum power of 1.05 MW was obtained, which is in agreement with its design target value. And the high efficiency of 40% without collector potential depression (CPD) was obtained with 0.8 MW. In the first and second 77 GHz gyrotrons, 0.8 MW 3.6 sec., 0.3 MW 60 sec operations have been achieved, but several issues due to the stray RF and velocity dispersion have been found, too. In consideration of these, the design improvement was performed to aim at 1.5 MW in the third tube. In the short pulse test, the maximum output power of 1.6 MW and the maximum total efficiency of 49.4% with CPD were obtained. In the long pulse test, the pulse length extended to 5 sec with 1 MW, 1800 sec with 0.1 MW, 1.6 sec with 1.5 MW. Total injection power of 3.1 MW to LHD plasma has been achieved. It is shown that the electron beam pitch factor ?? decreases with increasing of beam current, comparing with the experimental and calculation results.     

Design and Fabrication of Hybrid Piezomotor Applied in Precision Positioning Devices

The motor＇s configuration is designed and the dynamic analysis equations based on its simplified model are deduced. A testing system utilizing grating is set up to test this new motor, and the theoretical movement principle for the motor is proved by experiments. The pulse waveforms are applied to drive the motor to move in steps. The motor has a displacement resolution of 10 nm and a maximum velocity of 0.6 mm/ s. It can drive a 200 g slider whose range is 20 mm. A one-dimensional precision positioning platform is fabricated by using the new hybrid piezoelectric motor. The prototype is made up of two servomotors and two piezoelectric motors, which are controlled automatically by a computer. The positioning range of the platform is 10 cm.     

Glucose Detection Devices and Methods Based on Metal–Organic Frameworks and Related Materials

Assessment of glucose concentration is important in the diagnosis and treatment of diabetes. Since the introduction of enzymatic glucose biosensors, scientific and technological advances in nanomaterials have led to the development of new generations of glucose sensors. This field has witnessed major developments over the last decade, as the novel nanomaterials are capable of efficiently catalyzing glucose directly (i.e., act as artificial enzymes, therefore defined nanozymes) or to entrap enzymes that are able to oxidize glucose. Among other nanomaterials, metal–organic frameworks (MOFs) have recently provided a tremendous basis to construct glucose sensing devices. MOFs are large porous crystalline compounds with versatile structural and tuneable chemical properties. In addition, they possess catalytic, peroxidase-like, and electrochemical redox activity. This review comprehensively summarizes the general characteristics of MOFs, their subtypes, and MOF composites, as well as MOF-derived materials employed to construct electrochemical, optical, transistor, and microfluidic devices for the detection of glucose. They include enzymatic, nonenzymatic, wearable, and flexible sensing devices and methods. The review also outlines the design and synthesis of MOFs and the working principles of the different transduction-based glucose sensors and highlights the current challenges and future perspectives.     

Energy Transfer Probability Between Host and Guest in Doped Organic Electrophosphorescent Devices

提出了有机掺杂电致磷光器件中主体(TPD)与客体(Ir(ppy)3)间的能量转移几率表达式,并对能量转移过程进行了讨论.结果表明:(1)三态激子能量转移率(KHG,KGH)随主客体分子间距离R指数增加,KHG随客体分子间距离RGG增加有一个快的减少,且KHG/KGH随R或RGG减少而增加;(2)当R为0.8～1.2nm时,能量转移几率接近线性降低,而当R＜1.1nm时,RGG的变化能够被忽略,对于1.1nm＜R＜1.2nm的情况,RGG(＜1.6nm)对η起着越来越重要的作用;(3)当Forster能量转移率增加或Gibb's能减小时,η将会增加.     

Guest Editorial——TTA Special Section on Terahertz Materials and Devices

Lying between radio frequency and infrared radiation,terahertz(THz)wave encounters lots of difficulties to produce,detect,transmit,and modulate.Great efforts have been made to construct THz devices,including sources,detectors,switches,modulators,lenses,and filters.However,only moderate progresses have been made in THz generation and detection.Furthermore,the devices and techniques to control and manipulate THz waves are still in its infancy.Therefore,it is still a challenge to date to     

Actions,emotional reactions and cyberbullying – From the lens of bullies,victims, bully-victims and bystanders among Malaysian young adults

This paper examined the emotional reactions and actions involving cyberbullying, focusing on the cyber bullies, victims, bully-victims and bystanders. Gender analysis was conducted to examine if males and females behave and react differently. Self-administered surveys were used to gather data from a large sample of 1158 young adults, mostly university students in Malaysia (M_age?=?21.0?years; SD?=?2.16). Findings indicate the presence of cyberbullying perpetration after the schooling years, with 8% (N?=?93) bullying, 18.6% (N?=?216) victimization, 15.2% (N?=?174) bullying and victimization, and 53.4% (N?=?675) witnessing a cyberbullying incident in the past one year. Most of the bullies reported to be remorseful; however the majority did nothing after a perpetration. Most of the victims on the other hand, experienced anger, sadness and depression after a victimization with the majority claiming to have defended themselves (75%). The majority of the bully-victims regretted their actions, pitied the victims and felt angry after a cyberbullying perpetration/victimization. Bystanders mostly reported feeling pity for the victim and angry at the bullies, with the majority (61.5%) claiming to have defended the victims. However, 40% of them behaved indifferently out of fear retaliation. Finally, gender analysis revealed females to have significantly experienced more emotions than males whereas more males did nothing after a cyberbullying incident, both as victims and bystanders.