Three-phase inductive-coupled structures for contactless PHEV charging system

In this article, a new-type three-phase inductive-coupled structure is proposed for the contactless plug-in hybrid electric vehicle (PHEV) charging system regarding with SAE J-1773. Four possible three-phase core structures are presented and subsequently investigated by the finite element analysis. To study the correlation between the core geometric parameter and the coupling coefficient, the magnetic equivalent circuit model of each structure is also established. In accordance with the simulation results, the low reluctance and the sharing of flux path in the core material are achieved by the proposed inductive-coupled structure with an arc-shape and three-phase symmetrical core material. It results in a compensation of the magnetic flux between each phase and a continuous flow of the output power in the inductive-coupled structure. Higher coupling coefficient between inductive-coupled structures is achieved. A comparison of coupling coefficient, mutual inductance, and self-inductance between theoretical and measured results is also performed to verify the proposed model. A 1 kW laboratory scale prototype of the contactless PHEV charging system with the proposed arc-shape three-phase inductive-coupled structure is implemented and tested. An overall system efficiency of 88% is measured when two series lithium iron phosphate battery packs of 25.6 V/8.4 Ah are charged.     

Plasma charging damage mechanisms and impact on new technologies

Plasma charging damage is a serious concern in fab today. In this topic will be discussed mechanisms through which charging damage arises, how to characterize them, and how to minimize them at the different phases of circuit fabrication. The relation between oxide thickness and damage will be discussed highlighting the importance of characterization methods and reliability physics. Importance of charging damage on new technologies as copper and SOI will be discussed.     

Quantifying charging damage in gate oxides of antenna structures for WLR monitoring

A new method to quantify the reliability risk for gate oxide with plasma induced charging damage (PID) is established. Based on existing antenna test methodology the quantity of inflicted damage is expressed in a physical meaningful number by means of a simple model applicable for thick oxides (>5 nm).This model takes trap activation, trap filling, detrapping and also traps generation under constant current test condition (“revealing stress”, “diagnostic stress”) into account. For the corresponding development of the measurable external supply voltage with time an equation is derived. Experimental test data from different oxide thicknesses are fitted to this model equation to obtain its main parameters, the cross section values. These cross section values describe the probabilities for the different trap/detrap processes during stress. Cross section values thus found extend published data for lower electric fields to high electric fields necessary for a fast test.The number of plasma induced traps, which was added to the oxide during wafer processing, can now be determined by applying an electron trapping rate (ETR) test method, and combining it with our dynamic trap generation/filling model. The obtained number of PID related traps opens a path to calculate the corresponding reduction of oxide lifetime. Real measurement data are used to illustrate the method and its applicability to fast wafer level reliability (fWLR) monitoring.     

Sensitivity and limitations of plasma charging damage measurementsusing MOS capacitors structures

This work investigates the sensitivity and limitation of capacitor testing for measuring potential charging damage to gate oxides after a given plasma step. Ramp breakdown measurements are quick and easy to automate but lack sensitivity. Accelerated charge-to-breakdown measurements offers better sensitivity but with long measurement times. V-t measurements using the slope dV/dt after initial charging are found to be very sensitive to charge damage. The damage sensitivity of this method is high and involves tradeoffs between antenna ratio, testing current and testing time. All of which are critical to damage testing. Leakage measurements offers short measurement times and high sensitivity but are limited by the noise level of the measurement system and by the need to make good probe contact to the gate material     

Analytical expressions for tunnel currents in metal-insulator-metal (MIM) and metal-insulator-semiconductor (MIS) structures in a two-band model

A new closed-form approximation for the tunnel current in MIM and MIS structures is derived assuming a general E-k relationship and barrier shape. An upper limit for the error involved in this approximation is estimated. The existing closed-form expressions for the tunnel currents are discussed and their limitations are exposed.     

Unipolar current transport through metal-insulator-metal (MIM) structures,supplied with barrier contacts,in the diffusion limit

The diffusion-limited unipolar current density-voltage (j?V) dependencies through semi-insulating materials supplied with two barrier contacts have been computed. Two cases are treated. In the first, the sum of the two quiescent barrier thicknesses is less than the specimen thickness. Here there are three successive j?V regimes: At low voltages $\text{(}\text{less than}\text{V}{}_{\mathrm{th}}\text{=}\text{kT}\text{e}\text{),j∞V}$, at medium voltages, j∞√V, and at high voltages $\text{j∞}\text{V}\text{L}$ but much less in magnitude than the true ohmic current density. In the second case, the sum of the two quiescent barrier thicknesses exceeds the specimen thickness and the j∞ρV does not develop; only the two linear regimes are obtained separated by a short transitional interval over which the current is generally sublinear. The analysis is meant to apply to the practical cases of wide bandgap, insulating materials supplied with either rectifying or poorly characterized electrodes and to emphasize that a $\text{j∞}\text{V}\text{L}$ regime may develop that can easily be misinterpreted as Ohm's Law.     

Tunnelling current versus voltage characteristics in metal-insulator-metal films

The tunnelling current j(V) and the logarithmic conductivity σ(V) ≡ (1/j)(dj/dV) are calculated for exactly solvable one-dimensional models of metal-insulator-metal structures. When the tunnelling probability is calculated by the MWKB method, the logarithmic conductivity exhibits a single peak at a value of the applied voltage equal to the barrier height. When the tunnelling probability is calculated exactly this peak is shifted to a higher value of the applied voltage and additional peaks appear at even higher values of the applied voltage, depending on the thickness of the insulating film. This additional structure in σ(V) is due to “resonances” in the tunnelling probability which may or may not survive in three a dimensional calculation.     

Investigation of information loss mechanisms in EPROMs

The paper reports the results of accelerated life tests on p-and n-chanenl EPROMs, and compares the indication thus obtained with data from the field.The results of our experiments demonstrate that, even in recent production, contaminant diffusion significantly affects device reliability. The presence of this mechanism invalidates any effort to draw reliability information from lognormal plots of the cumulative distribution of the times to failure of all the bits in a device or in a set of devices: only the times to first bit failure for the devices of a batch should be considered. Furthermore, charge loss and contaminant diffusion seem to be uncorrelated processes.From the point of view of reliability it seems reasonable to conclude that, in spite of their increased complexity, 16 K n-channel EPROMs promise to be more reliable than 2 K devices, thanks probably to the improved technology.     

Fabrication and modeling of multi-layer metal-insulator-metal capacitors

This paper presents the fabrication and modeling for capacitance-voltage characteristics of multi-layer metal-insulator-metal capacitors.It is observed that,due the applied electric field,the effective dielectric constant of the stack was increased due to the accumulation of charges at the interface of high-to-low conductance materials.It is observed that the Maxwell-Wagner polarization is dominant at low frequencies (＜10 kHz).By introducing carrier tunneling probability of the dielectric stack,the model presented in this paper shows a good agreement with experimental results.The presented model indicates that the nonlinearity can be suppressed by choosing the similar permittivity dielectric materials for fabrication ofmultilayer metal insulator metal capacitors.     

Determination of low energy barriers in metal-insulator-metal tunneling junctions

Previous evaluations of the logarithmic derivative d/dV(ln J) of the tunnel current J with respect to voltage V for M1-I-M2 junctions are extended to models having extremely low metal-insulator energy barriers. It is shown that also in these cases the quantity d/dV(ln J) can exhibit pronounced maxima at voltages corresponding approximately to the metal-insulator barrier heights φ₁ and φ₂ of the junction. This result could be of interest in relation to tunneling through so-called artifical barriers where the investigation of the voltage and the temperature dependence of the current indicate in some cases very low energy barriers.     

Analog characteristics of metal-insulator-metal capacitors usingPECVD nitride dielectrics

The frequency dependence of PECVD nitride and LPCVD oxide metal-insulator-metal (MIM) capacitors is investigated with special attention for precision analog applications. At measurement frequencies of 1.0 MHz, nitride MIM capacitors show capacitance linearity close to that of oxide MIM capacitors, indicating potential for precision analog circuit applications. Due to dispersion effects, however, nitride MIM capacitors show significant degradation in capacitor linearity as the frequency is reduced, which leads to accuracy limitations for precision analog circuits. Oxide MIM capacitors are essentially independent of frequency     

Leakage mechanisms in the heavily doped gated diode structures

A leakage current model is presented which shows very good agreement with reported experimental results on gated diode structures with contemporary ULSI dimensions. The leakage current is modeled as the Shockley-Read-Hall generation current, enhanced by the Poole-Frenkel effect and trap-assisted tunneling. The model shows very good agreement on gate voltage, temperature, and oxide thickness dependence for the normal operating voltage range. It is found from the model that the doping range from 2×10¹⁸ to 1×10¹⁹ cm ^-3 gives the most significant degradation to the leakage characteristics in trench-type DRAM cells and the drain of MOSFETs     

Characteristics of metal-insulator-metal diodes as generators offar-infrared radiation

Characteristics of metal-insulator-metal (MIM) diodes which are used as mixer-generators of far-infrared (FIR) radiation have been investigated for nine different diode base metals. It was found that a W-Fe diode works as effectively as a W-Co diode in generating tunable FIR radiation by mixing two CO₂ lasers and microwave radiation. The bias dependences of W-Ni, W-Co, and W-Fe MIM diodes have also been examined. Observed bias results can be predicted by analyzing their current-voltage characteristics     

Structural mechanisms of photoeffect in polyimide structures containing heterocyclic fragments

Trends in the variation in the quantum yields of charge-carrier photogeneration in polyimide structures containing heterocyclic fragments are studied. It is shown that the efficiency of sensitization of polyimides depends on the donor and acceptor properties of the fragments of monomeric units of the polyimide. It is established that the range of spectral sensitivity for heterocyclic fragments representing intramolecular complexes with charge transport is wider than that for heterocycles that do not represent such complexes.     

Single electron charging and single electron tunneling in sub-micron AlGaAs/GaAs double barrier transistor structures

Transport phenomena in a specially optimized vertical asymmetric sub-micron Al_0.28Ga_0.72As/GaAs double barrier structure with modulation-doped barriers is investigated by applying a bias to a special Schottky side gate, which allows the effective area of the conducting channel to be finely “tuned”. For a sufficiently small device, the electrical properties of the controllable quantum dot bounded by well defined heterostructure barriers and an adjustable side wall potential are expected to be governed by single electron charging, and single electron resonant tunneling. Single electron transistor (SET) operation is possible because the number of electrons in the dot, n, can be varied one-by-one with the side gate. The drain current flowing through the conducting channel in response to a small drain voltage is strongly modulated by the gate voltage close to “pinch-off” as n approaches zero, and oscillations in the drain current persist up to about 25 K. A gate modulated zero current region of Coulomb blockade, step-like features, and resonances exhibiting negative differential resistance are clearly observed at low bias. Although this technology is very promising for the realization of SET operation at temperatures well above 4.2 K, the temperature dependence of the Coulomb blockade is an important limitation. We describe the evolution of the conductance oscillations and the degradation of Coulomb blockade with temperature from 0.3 K up to 25 K, and propose that co-tunneling in a small system containing just a “few” electrons in which the zero-dimensional energy level spacing is significant and comparable to the Coulomb charging energy is important, and is likely to be more complex than that documented for large planar dot structures containing “many” electrons.     

激光二极管点火机理研究

通过理论分析、实验和数值计算研究了激光二极管点火的热作用机理，分析了点火的临界值及影响因素。一般情况下，含能材料的激光二极管点火机理主要表现为热作用；激光功率密度是影响点火的重要因素。     

Investigation of localized coupled-cavity modes in two-dimensionalphotonic bandgap structures

We present a detailed study of the localized coupled-cavity modes in 2-D dielectric photonic crystals. The transmission, phase, and delay time characteristics of the various coupled-cavity structures are measured and calculated. We observed the eigenmode splitting, waveguiding through the coupled cavities, splitting of electromagnetic waves in waveguide ports, and switching effect in such structures. The corresponding field patterns and the transmission spectra are obtained from the finite-difference-time-domain (FDTD) simulations. We also develop a theory based on the classical wave analog of the tight-binding (TB) approximation in solid state physics. Experimental results are in good agreement with the FDTD simulations and predictions of the TB approximation     

Theoretical and experimental responsivity of fir antenna coupled metal-insulator-metal detectors

In this work we report a complete theory of the metal-insulator-metal, antenna coupled, mm and sub-mm detectors. The voltage-power responsivity is simply derived from the geometrical antenna proprieties and the electrical junction characteristics. The calculated responsivity simply foresees our experimental results in the sub-mm — mm range and well fits all the previously reported data     

RF model of 3-RC network structure for metal-insulator-metal capacitor

A radio-frequency (RF) equivalent circuit model for the metal-insulator-metal (MIM) capacitor with both side bottom plate contact is presented. The proposed model consists of 3-distributed RC networks and substrate networks. The accuracy of the MIM capacitor model is verified for Z-parameters, effective capacitance (C ^{), quality factor (Q), and MIM capacitor impedance (Z ) up to 20 GHz. The effects of substrate network components on MIM's frequency characteristics are also analysed through Z-parameters. Finally, the cutoff frequency of the MIM is extracted from Q-factor and Z .}     

Theoretical and experimental responsivity of fir antenna coupled metal-insulator-metal detectors

In this work we report a complete theory of the metal-insulator-metal, antenna coupled, mm and sub-mm detectors. The voltage -power responsivity is simply derived from the geometrical antenna proprieties and the electrical junction characteristics. The calculated responsivity simply foresees our experimental results in the sub-mm — mm range and well fits all the previously reported data