The three major failures of electrical contacts for automotive relay applications are: contact welding (or contact sticking), high contact resistance and severe contact erosion due to switching arcing. With the demand of high power and multiple functions of automotive vehicles, the switching current has be dramatically increased, it results in higher failing rate, in particular for contact welding. On the other hand, the miniaturization of electromechanical relays has lead to the reduction of mechanical spring force. This not only results in the earlier contact welding but also makes the relay more susceptible to the contact resistance and arc erosion failures. This paper is a review of most recent studies on these three failure aspects. It describes the progress in the understanding of contact welding caused by short arcing and high contact resistance due to contamination of particles and films in relay manufacturing process and also it review the material transfer due to switching arcing. At the end, the brief considerations of electromechanical relays used in 42 volts have also been given.

NMAC is a function for message authentication based on cryptographic hash functions such as SHA. It is shown to be a secure message authentication code if its compression function with fixed input length is a secure message authentication code and its iterated hash function with variable input length constructed with the compression function is weakly collision resistant. In this article, two results are shown on the strength of the weak collision resistance of the iterated hash function in NMAC. First, it is shown that the weak collision resistance of the iterated hash function in NMAC is not implied by the pseudorandomness of its compression function even if the MD-strengthening is assumed. Second, the weak collision resistance of the iterated hash function in NMAC implies the collision resistance of its compression function if the compression function is pseudorandom.

Precise designs are presented for sapphire rod resonators of three types, which have been proposed by the IEC/TC90/WG8 in the standard measurement method of the surface resistance Rs of high-Tc superconductor (HTS) films; an open-type, a cavity-type and a closed-type. In order to separate TE011 and TE013 modes, which are used in Rs measurements, from the other modes, appropriate dimensions for these three resonators are determined from mode charts calculated from a rigorous analysis based on the mode matching method, taking account of an uniaxial-anisotropic characteristic of sapphire. Comparison of the open-type resonator with the closed-type is performed. For the open-type, the unloaded Q values of both the TE011 and TE013 modes are reduced by radiations of a leaky state TM310 mode. Finally, validity of the design and a two-sapphire-rod-resonator method will be verified by experiments.

In this paper, we propose the CMOS implementation of a multiple-valued memory cell using -shaped negative-resistance devices. We first propose the construction of a multiple-stable circuit that consists of -shaped negative-resistance devices from four enhancement-mode MOSFETs without a floating voltage source, and connect this in parallel with a unit circuit. It is shown that the movement of -shaped negative-resistance characteristics in the direction of the voltage axis is due to voltage sources. Furthermore, we propose the construction of a multiple-valued memory cell using a multiple-stable circuit. It is shown that it is possible to write and hold data. If the power supply is switched on, it has a feature which enables operation without any electric charge leakage. It is possible, by connecting -shaped negative-resistance devices in parallel, to easily increase the number of multiple values.

A device structure for polymer Schottky diode, which has the glass chimney as a dopant reservoir enabling the reduction of series resistance without cathode corrosion, has been proposed. Doping with the acetonitrile solution of FeCl3 in the device resulted in the increase in the forward-bias current by one order of magnitude without notable increase in reverse-bias current, suggesting that the doping reduced the series resistance. It is found that the penetration speed depends on the solvents. Short time doping with the nitromethane solution of FeCl3 resulted in the increase by three orders of magnitude. However, doping for a long period yielded the considerable increase in the reverse-bias current due to the complete penetration of dopatn solution. When the upper opening of glass chimney of device is left opened and the sample after doping stored in air, the forward-bias current of the device reduced rapidly due to the undoping and/or degradation of polymer. It is possible to protect the degradation of device characteristics after doping, by sealing the chimney and storing the device in vacuum.

InGaP/GaAs HBT with novel ledge coupled capacitor (LCC) structure has been proposed and demonstrated for the first time. The LCC employs an extrinsic InGaP ledge layer as a capacitor parallel to the base resistor. This configuration enables feeding RF signals directly into the base without passing them through the base resistor. With the fabricated HBT, no increase of leakage current between emitter and base electrode was observed. The maximum oscillation frequency (fmax) of the HBT was improved by 10 GHz as compared with an HBT without the LCC.

High-frequency characterization and delay-time analysis have been performed for a short channel AlGaN/GaN heterojunction FET. The fabricated device with a short gate length (Lg) of 0.07 µm exhibited an extrinsic current gain cutoff frequency of 81 GHz and a maximum frequency of oscillation of 190 GHz with a maximum stable gain (MSG) of 8.2 dB at 60 GHz. A new scheme for the delay-time analysis was proposed, in which the effects of rather large series resistance RS + RD are properly taken into account. By applying the new scheme to a device with Lg=0.25 µm, we obtained an effective high-field electron velocity of 1.75107 cm/s, which is consistent with our previous results calculated using Monte Carlo simulation.

The frequency dependence of surface resistance Rs of high temperature superconductor (HTS) films are measured by a novel measurement method using four TE0mp modes in a sapphire rod resonator. At first, a loss tangent tan δ of the sapphire rod and Rs of the HTS films are evaluated separately from the results measured for the TE021 and TE012 modes with close resonant frequencies. Secondly, Rs values at two different resonant frequencies for the TE011 and TE022 modes are measured using a well-known relation for sapphire tan δ/f = constant, where f is a frequency. Rs values of HoBa2Cu3O7-x thin films were measured in the frequency range of 10 to 43 GHz by using four sapphire rod resonators with different sizes. As a result, it is found that these measured results of Rs have a characteristic of frequency square.

In recent years, sliding electric contacts came to be often used under very severe conditions such as high temperature, extremely low temperature, high vacuum, etc. Conventionally, solid lubricants having excellent properties in lubricating performance are generally used compositely with a metal of high electric conductivity, because of their high electrical resistivity. In the present study, we proved that more excellent sliding electrical contacts can be produced with a design made by controlling the distribution on contact surface of a solid lubricant having excellent lubricating performance and of a metal with high electric conductivity through expansion of Greenwood's theory.

In this paper, we try to establish a power law for contact resistance versus force Rc = KcFc-n , and we determine via experimental measurements and theoretical calculations, the constants n and Kc in the force range (1 mN-4 N) for bulk metal (Ag, Au, Pd, Ni) used in various applications (microswitches, connectors). The main experimental results of contact resistance are the occurrence of two decrease domains versus progressive load indentation. The first regime corresponds to the earlier touch of the coupon by the probe at force < 0.1 N. This elastic regime evolves to a plastic regime for medium force > 0.1 N. At the transition the exponent value n changes from 0.33 to 0.5 and induce Kc value increasing. Theoretical and computational approaches applied to the elasto-plastic model, confirm the occurrence of these two regimes. Although the calculated values of n are in good agreement with experimental values, some discrepancy between measured and calculated Kc values take place.

The potential drop and the self-heating due to the contact resistance at the interface between silicide and silicon are incorporated in the device simulation for ESD protection devices. A transition region is provided at the interface and the resistivity is calculated by scaling the contact resistance by the length of the region. The power density used in the heat conductive equation is calculated by using the potential drop and the contact resistance in the transition region. The validity of the present approach is checked by the Monte Carlo simulations. Using the technique, influence of the contact resistance on self-heating in an ESD protection device with the grounded gate MOSFET structure is simulated.

In this paper, we propose the CMOS implementation of neuron models for an artificial auditory neural network. We show that when voltage is added directly to the control terminal of the basic circuit of the hardware neuron model, a change in the output firing is observed. Next, based on this circuit, a circuit that changes with time is added to the control terminal of the basic circuit of the hardware neuron model. As a result, a neuron model is constructed with ON firing, adaptation firing, and repetitive firing using CMOS. Furthermore, an improved circuit of a neuron model with OFF firing using CMOS which has been improved from the previous model is also constructed.

A new measurement method using two resonance modes, the TE021 and TE012 modes, in an image-type dielectric resonator is proposed to measure the surface resistance Rs of only one high-Tc superconductor (HTS) film and the loss tangent tan δ of a sapphire rod separately, precisely and nondestructively. The image-type resonator is constructed by placing a sapphire rod in a bottom of a conductor cavity made of two HTS films and a copper ring. This resonator is designed from the mode charts calculated on the basis of the rigorous analysis by the mode matching method, taking account of an uniaxial-anisotropic characteristic of sapphire. It is verified that the mode charts are also effective to identify many resonance modes observed in measurement. The temperature dependence of Rs of one YBCO film was measured at 19.3 GHz by this method. The measured result agreed very well with one measured by the conventional two-dielectric resonator method. As a result, it was verified that this method is useful to evaluate Rs value of one HTS film with no damage.

Load/unload techniques are widely used in mobile hard disk drives which have to endure external shocks frequently. ABS designs must consider both the load/unload performance and the shock resistance performance. Three ABS designs with different positions of the suction force center are studied in simulation. It is observed that when the position of the suction force center moves frontward, the anti-shock performance improves, but the unload performance degrades, and vice versa. A slider is not necessary to be designed to have its suction force center significantly behind of its geometric center, as the traditional load/unload sliders do. Instead, the suction force center can be designed near the geometric center if the hook limiter is used.

A practical method of measuring the contact resistance of a phosphorus-doped poly-Si plug formed on a lightly phosphorus-doped diffusion region in DRAM memory cells is described. Contact resistance was obtained electrically, using ordinary contact-chain test structures, by changing the measurement of the substrate bias. This separated the bias-dependent resistance of the lightly doped diffusion layer from the total resistance. The method was used experimentally to evaluate the feasibility of forming low-resistance contacts down to a diameter of 130 nm for giga-bit DRAMs. Electrical measurement showed that reducing the interface resistance between the poly-Si plug and the lightly doped diffusion layer was effective for forming low-resistance contacts, though a specific interface layer could not be detected by TEM observation.

Ultra shallow low-resistive junction formation has been investigated for sub-100-nm MOSFETs using antimony implantation. The pileup at the Si/SiO2 interface and the resulting dopant loss during annealing is a common obstacle for antimony and arsenic to reduce junction sheet resistance. Though implanted arsenic gives rise to pileup even with a few seconds duration RTA (Rapid Thermal Annealing), antimony pileup was suppressed with the RTA at relatively low temperature, such as 800 or 900. As a result, low sheet resistance of 260 Ω/sq. was obtained for a 24 nm depth junction with antimony. These results indicate that antimony is superior to arsenic as a dopant for ultra shallow extension formation. However, increase in antimony concentration above 11020 cm-3 gives rise to precipitation and it limits the sheet resistance reduction of the antimony doped junctions. Redistribution behaviors of antimony relating to the pileup and the precipitation are discussed utilizing SIMS (Secondary Ion Mass Spectrometry) depth profiles.

A new method is proposed for determining the parasitic extrinsic resistances of MESFETs and HEMTs from the measured S-parameters under active bias. The proposed method is based on the fact that the difference between drain resistance (Rd) and source resistance (Rs) can be found from the measured S-parameters under zero bias condition. It is possible to define the new internal device including intrinsic device and three extrinsic resistances by eliminating the parasitic imaginary terms. Three resistances can be calculated easily via the presented explicit three equations, which are induced from the fact that 1) the real parts of Yint,11 and Yint,12 of intrinsic Y-parameters are very small or almost zero, 2) the transformation relations between S-, Z-, and Y-matrices. The modelled S-parameters calculated by the obtained resistances and all the other equivalent circuit parameters are in good agreement with the measured S-parameters up to 40 GHz.

The measurement sensitivity of microwave surface resistance, Rs, of high temperature superconducting (HTS) thin films using half-wavelength microstrip resonator with copper and HTS ground plane is analyzed for fundamental and higher order modes of the resonator. The estimated sensitivity of Rs-measurement is at least an order of magnitude greater at fundamental resonant frequency compared to when measured using higher order harmonic modes.

A coaxial cable measurement system applicable up to 60 GHz in the cryogenic temperature is developed by using V-connectors. In this system, the fine location of coupling loop antennas can be adjusted by three-dimensional mechanical stages in the low temperature region. In order to verify usefulness of this system, the temperature dependence of surface resistance (Rs) of Y-Ba-Cu-O (YBCO) films was measured at 30 GHz by the two-dielectric resonator method using TE011- and TE013- mode sapphire rod resonators. The measured result of Rs was 0.5 mΩ at 30 GHz and 20 K, which was 1/40, compared with those of copper plates.

The methods for the transverse mode control and temperature characteristics improvement in 850 nm oxide confined vertical cavity surface emitting lasers (VCSELs) were investigated. For transverse mode control, dielectric aperture was demonstrated to suppress higher order modes. Substitution of AlAs for Al0.9Ga0.1As in partial bottom DBR was demonstrated to reduce thermal resistance of the devices and to enable operation in high temperature of 85.