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1.
Yunlong Li Groeseneken G. Maex K.. Tokei Z.. 《Device and Materials Reliability, IEEE Transactions on》2007,7(2):252-258
The real-time conduction mechanism during bias stress of three silica-based intermetal dielectrics in Cu damascene structures was investigated. High-frequency capacitance and I-V measurements were intermittently inserted into the process of bias stress to monitor the conduction mechanism change with time. All experiments show that the capacitance is constant, and the I-V curve slope decreases with bias stress and converges to half of the initial value. Based on an extended Frenkel-Poole model with compensation effects, we propose that the changes of the acceptor/donor densities in the dielectrics result in the apparent I-V curve slope evolution, but the dominant conduction mechanism is always bulk controlled. 相似文献
2.
The cells of a capacitive energy store with a semiconductor switch are studied, when the switch consists of reverse-switched dynistors and power diodes. Particular attention is paid to the operation of semiconductor switches with surge currents, when the semiconductor structures are strongly heated. The operating conditions of the switches in programmed discharge are considered. 相似文献
3.
《Dielectrics and Electrical Insulation, IEEE Transactions on》2006,13(2):394-399
At a stoichiometrical relation of silicon and oxygen during the growth of a rapid thermal silicon-oxide layer (RTO) the electrical parameters of the corresponding metal-insulator-semiconductor capacitor show significant behavior. Combining the Henry-Dalton law and the Boyle-Mariotte law with the Deal-Grove model allows an estimation of the fundamental (T, t, C) process, parameters, temperature, time and concentration of the reactive gas for a stoichiometrical processing of ultra thin SiO/sub 2/ films. Electrical measurements show the (T, t, C)-dependency of I-V, time dependent dielectric breakdown (TDDB) and C-V measurements especially of direct tunneling currents j/sub DT/, relative difference of tunneling currents /spl Delta//sub RDT/, charge-to-breakdown Q/sub BD/ and interface state density D/sub it/. 相似文献
4.
Meena 《Integrated ferroelectrics》2017,184(1):158-165
ABSTRACTIn the present work, Ag nanoparticles prepared by chemical reduction were used to synthesize Ag-starch nanocomposites. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to ascertain the formation of Ag-starch nanocomposites. Current-voltage (I-V) measurements reveal that the conductivity of starch increases with increasing concentration of Ag nanoparticles. I-V data was further analysed to ascertain the actual conduction mechanism responsible for charge transport in starch and Ag-starch nanocomposites. Poole-Frenkel (PF) emission was found to be dominant conduction mechanism responsible for increased conductivity of Ag-starch nanocomposites. 相似文献
5.
Luna E. Guzman A. Sdnchez-Rojas J.L. Sanchez J.M. Munoz E. 《IEEE journal of selected topics in quantum electronics》2002,8(5):992-997
Double-barrier quantum-well infrared photodetectors are promising for operation in the midinfrared region. In this paper, we present a series of novel molecular beam epitaxy (MBE)-grown devices based on modulation-doped (MD) AlGaAs-AlAs-GaAs structures that exhibit a remarkable responsivity at zero bias (0.05 A/W) at 4.6 /spl mu/m. Since the photovoltaic properties are strongly dependent on the symmetry of the potential profile, we have systematically varied the position of the dopant in the barriers for a series of single-color detectors. Low-temperature photocurrent spectra and current-voltage (I-V) characteristics (in the dark and under illumination) show that the location of the dopant is a relevant design parameter, due to its role in the photovoltaic behavior (i.e., the presence or absence of zero bias signal). The performance of the MD devices is compared with that of a detector with doping in the center of the well and otherwise the same structure. In particular, the responsivity and detectivity seem to be higher for the MD detectors than for well-doped samples, especially when the dopant is located in the barrier closest to the substrate. Therefore, we have chosen that MD dopant profile when designing and growing, to our knowledge, the first 3-5 /spl mu/m two-color detector, with simultaneous detection at 3.8 and 4.4 /spl mu/m. 相似文献
6.
为了研究高温超导电缆在直流和交流载流情况下伏安特性的变化规律,提出基于第二代YBCO高温超导体的冷绝缘超导电缆交直流伏安特性测试方法,搭建了伏安特性测试实验系统,通过对一根0.2m长,110k V/1.5k A高温超导电缆样缆的交直流伏安特性进行测试,获得了超导电缆在直流、30Hz、100Hz和工频载流下伏安特性变化规律。结果表明,超导电缆的直流伏安特性曲线呈现E-J指数关系,且失超变化清楚,而交流下当超导电缆通流值低于直流临界值时,交流伏安特性曲线变化平缓,之后随通流能力增加后该曲线呈逐渐上升趋势,超导电缆没有出现明确的失超变化点。研究结果对于开展超导电缆运行稳定性研究提供了较大的参考价值。 相似文献
7.
The electrical and gravimetric properties of langasite, La3Ga5SiO14, are related to its underlying defect and transport processes via previously developed predictive defect and transport models.
These models are used here to calculate the dependence of the partial ionic and electronic conductivities and the mass change
for langasite as functions of temperature, dopant type and level and pO2. Doping strategies devised for minimizing conductivity in langasite based on use conditions are described. For example, the
required dopant level to achieve minimum conductivity and thus minimum electrical losses in acceptor-doped langasite is shown
to depend on the operating pO2. Likewise intrinsic mass changes in langasite, dependent on dopant level, pO2 and temperatures, if high enough, can mask mass changes induced in active layers applied to langasite when used as a microbalance.
For example, the model predicts that the dopant level in donor-doped langasite has less of an impact on intrinsic mass change
due to external environmental changes when compared to acceptor-doped langasite. The models are also applied in defining acceptable
operating limits needed to achieve and/or the design of properties for desired levels of microbalance resolution and sensitivity. 相似文献
8.
P. Markondeya Raj Baik-Woo Lee Devarajan Balaraman Rao R. Tummala 《Journal of Electroceramics》2011,27(3-4):169-175
Hydrothermal processing can deposit crystalline ferroelectric films at low temperatures of less than 150°C to achieve permittivities above 100. Such a process, hence, can be attractive in integrating thin film capacitors in organic, silicon or flex substrates. However, their poor insulation strength leading to high leakage current can prevent their wide acceptance. Lattice defects such as hydroxyl groups are attributed to their high leakage currents and lower Breakdown Voltages (BDVs). With appropriate thermal treatments, majority of the OH groups can be removed, leading to improved insulation characteristics. The leakage current behavior of as-synthesized and post-baked hydrothermal thin films are analyzed with various conduction models. The room temperature I-V characteristics are attributed to a combination of ionic and Space-Charge-Limited (SCLC) conduction models for films baked at 160°C while higher baking temperatures of 350°C agree well with Poole-Frenkel type conduction, with an activation energy of 0.57 eV for the defects. The defects, which are presumably OH groups or oxygen vacancies embedded in the barium titanate lattice, act as shallow traps and the trapping and detrapping results in easier conduction. A brief perspective is provided on the suitability of such a hydrothermal thin film capacitor approach for power supply applications. 相似文献
9.
The addition of transition metal elements such as Co is necessary to realize highly non-linear ZnO based varistors. The relation between the oxidation states of Co ions and the appearance and disappearance of the non-linear I-V characteristics was studied in ZnO-CoO based compositions. Pressed bodies were sintered at 1430°C in an oxygen atmosphere followed by annealing at various temperatures in air. The I-V characteristics of these specimens were then measured. The appearance and disappearance of the non-linear I-V characteristics was found to reversibly occur depending on the annealing temperatures and to be closely related to the oxidation states of the Co ions. 相似文献
10.
《Device and Materials Reliability, IEEE Transactions on》2008,8(3):536-542
11.
一种电压源型有源电力滤波器的新型控制方法 总被引:1,自引:1,他引:0
研究了电压源型有源电力滤波器、电源及非线性负载三者之间的能量交换机理,分析了变流器直流侧电容电压的稳定问题,提出了维持直流侧电容电压稳定的新方法。在此基础上提出了一种电压源型有源电力滤波器的新型控制方法,详细推导了控制方程。该方法无需检测三相负载电流和三相输入电压,无需计算参考电流、无功电流和谐波电流;只需检测两相电源电流和直流侧电容电压,通过简单运算就可直接求出每个开关周期内各开关的占空比,实现滤波器的控制。仿真研究结果表明新型控制方法能有效补偿谐波电流和无功电流,抑制负载不对称。 相似文献
12.
Li H.M. Fouracre R.A. Crichton B.H. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1995,2(5):866-874
In this paper, the relationship between the frequency and time domain windows is discussed. From this study an appropriate time window for transient current measurements may be chosen so that reliable low frequency dielectric data can be obtained. The suitability of applying either Fourier transform or the Hamon approximation for the derivation of low frequency responses is discussed for transient currents with different shapes. With water-treed LDPE samples aged in the laboratory, measurements of transient currents, with subsequent transformation into the frequency domain, show a loss peak at ~10-4 to 10-3 Hz when moisture is retained in the samples. Even with free water removed, a higher dielectric loss is observed in water treed samples compared to virgin samples. The relaxation behavior may serve as an indicator of water treeing in polymeric cable insulation. The results of both transient measurements and TSDC results can be affected significantly by the treatment conditions of the samples. The application of vacuum to a water treed sample can alter the activation energy of the conduction process and the TSDC spectra 相似文献
13.
《IEEE transactions on neural systems and rehabilitation engineering》2009,17(5):469-477
14.
Lerner P. Cutler P.H. Miskovsky N.M. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1997,4(6):827-829
Recently Geis fabricated a composite cold cathode emitter made of diamond doped by substitutional nitrogen on a roughened metallic substrate, which is characterized by high field emission currents at very low power. Using an internal field emission mechanism through the Schottky barrier at the metal diamond interfaces to populate the conduction band of diamond, we have developed a quantitative theory to describe the operation of such a device. The calculated I-V characteristics are in good agreement with the experimental results of Geis, et al 相似文献
15.
Akyuz M. Gao L. Cooray V. Larsson A. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2001,8(4):665-672
A study has been conducted on positive streamer discharges in air at atmospheric conditions for a three-electrode system, The electrode system consisted of two parallel planes (one grounded and one supplied with a negative dc voltage) and a small, insulated needle, sticking out from the center of the grounded plane. A triggering positive square impulse voltage of 5 μs duration was applied to the insulated needle and the currents associated with the streamer discharge were measured simultaneously on all three electrodes. During the streamer propagation, the current measured at the needle was the conduction current while the other two were the displacement (or capacitive) currents generated by the movement of charge in the electrode gap. The objective of this study is to identify the three currents and to investigate if simple representations of the streamer can reproduce the displacement currents measured at the plane electrodes. Two models for the streamer were applied: (1) a charged sphere moving in the background field and (2) a channel with a constant voltage gradient extending in the gap. In both models it was assumed that the streamer propagated with a constant velocity, which was estimated from the measurements. The motion of the streamer was simulated by a series of electrostatic calculations, using a field calculation program. Comparison of the measurements with the simulations indicates that the charge of the streamer is confined to a spherical region (i.e. streamer head) and it is increasing continuously during its advancement in the electrode gap. A discussion on advantages and disadvantages with the two investigated models (sphere vs. channel with potential gradient) is conducted, and a possible hybrid model is suggested. In the proposed model, features from both considered streamer representations are included 相似文献
16.
Pankaj Misra Shojan P. Pavunny Yogesh Sharma Ram S. Katiyar 《Integrated ferroelectrics》2014,157(1):47-56
The unipolar resistive switching characteristics of the amorphous LaLuO3 thin films deposited by pulsed laser deposition have been studied. Reliable and repeatable nonvolatile switching of the resistance of LaLuO3 films was obtained between two well defined states of low and high resistance with nearly constant resistance ratio ~107 and non-overlapping switching voltages in the range of 0.66-0.83 V and 1.9-2.7 V respectively. The temperature dependent measurement revealed metallic and semiconducting behavior in low and high resistance states respectively. The switching between low and high resistance states was attributed to the change in the separation between oxygen vacancies in light of the correlated barrier hopping theory. The current conduction mechanism of the device in high-resistance state followed the Poole's law, whereas the conduction in low-resistance state was found to be dominated by percolation. The resistance of low and high resistance states of the film showed no obvious degradation for up to ~104 seconds indicating good retention. The achieved characteristics of the resistive switching in LaLuO3 thin films seem to be promising for futuristic nonvolatile memory applications. 相似文献
17.
J. F. Scott 《组合铁电体》2013,141(1-3):1-12
Abstract A somewhat qualitative review of leakage currents J(V,t) in perovskite oxides is presented. It is stressed that space-charge-limited currents (SCLCs) are not alternatives to ionic conduction, Schottky emission, Poole-Frenkel, or Fowler-Nordheim tunneling, but can occur whenever currents due to any of those mechanisms reach a certain threshold and are no longer limited by the details of the metal electrode-ferroelectric interface. Standard metal-semiconductor band models that exclude surface states fail qualitatively to account for the experimental dependences of leakage currents and breakdown voltages on electrode work function; the correct model is metal-n-p-n-metal, with surface donor-state trapping. A discussion of conduction properties in these materials is presented from an ionic conductor viewpoint. 相似文献
18.
A novel approach combining conventional contact- and projection-lithography techniques has been devised to implement microelectrodes, down to submicron size, across isolated site-specific features as small as 2–3 micron. For both ex-situ and in-situ electrical characterization, such features of interest are isolated interfaces and grain boundaries in electroceramics and multilayer devices, including those in as-prepared TEM specimen. The procedure has been discussed for implementing 4-probe microelectrodes across several individual isolated grain boundaries of a commercial ZnO varistor containing 2–10 micron size grains. In addition, we discuss the results from dc 4-probe I-V and ac 2-probe impedance measurements across individual grain boundaries, and dc 2-probe I-V and ac 2-probe impedance measurements from grain interiors isolating these grain boundaries. Over and above the generally observed properties of isolated grain boundaries, the measurements reveal (1) inhomogeneity and applied-bias-polarity dependent asymmetry in the nonlinear I-V characteristics of grain boundaries, (2) possible presence of non-ohmic electrode-ceramic contact resistance in 2-probe measurements, and (3) a gradual process of irreversible degradation of the nonlinear I-V behavior with respect to thermal runaways upon application of a dc bias across isolated grain boundaries. 相似文献
19.
Dluzniewski M. Staryga E. Bak G.W. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2001,8(3):418-421
Electrical conduction of metal/DLC/silicon/metal heterostructures has been investigated, Both DLC/p-Si and DLC/n-Si systems shows rectifying properties. The current-voltage (I-V) characteristics of the heterostructures can be described well by the simplified diode equation with the ideality factor between 21.2 and 3.25, decreasing with increasing temperature. The directive tendency of I-V characteristics is independent of the type of silicon substrate. A simple qualitative band model of DLC/Si junction is proposed 相似文献