摘要:

AbstractThis paper describes the theoretical and experimental results on the propagation of boundary acoustic waves along a ZnO layer between two materials. It was proven theoretically that the boundary acoustic waves propagate in SiO2/ZnO/SiO2, SiO2/ZnO/PYREX and SiO2/ZnO/(Z – X)Si structures. The propagation velocity, electromechanical coupling coefficientK2, and the concentration of energy to the mid‐layer were calculated as a function of the ZnO film thickness. The thermal coefficient of delay time TCD was also calculated for the SiO2/ZnO/SiO2and SiO2/ZnO/(Z – X)Si structures, showing that a certain ZnO film thickness provides zero TCD. Next, requirements of a glass substrate for propagation of boundary acoustic waves along the ZnO film sandwiched by SiO2and glass substrate or glass film and glass substrate is discussed. As a result, as the thickness of the ZnO film and the second velocity increase, the boundary acoustic wave has a better chance to exist. Finally, the device with SiO2/ZnO/SiO2structure was actually fabricated and it was confirmed that the boundary acoustic wave was excited and propagated in the device. If the Rayleigh wave characteristic is taken into account, the experimental and theoretical results

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710501

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractIn VLSI development, many experiments are required to determine the process flow and the process specifications for wafer treatment. Therefore, the kinds of experiments have become tremendous for the development. Since the process specifications are often different from wafer to wafer, the management of many sort and small quantity lots is essential.In this paper, a distributed wafer tracking system for VLSI development is described. This distributed computer system is constituted of personal computers and a host computer. A new method was developed and adopted in which the process specifications are pre‐registered on 3.5 inch floppy discs as well as a new data management architecture. This system realizes higher reliability and flexibility using simple hard/software construction and flexibility than the conventional centralized syste

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractTo realize a large‐capacity, high‐speed ECL‐compatible SRAM with an access time comparable to that of bipolar ECL RAMs, we have investigated a circuit configuration and optimizing method for SRAMs with peripheral circuits consisting of BiCMOS circuitry except for memory cells on the basis of submicron BiCMOS technology. A predecoder configuration with a bipolar small‐amplitude logic circuitry is proposed and the number of predecoders that minimizes the decoder power dissipation is determined. Also, a word‐driver circuit that utilizes an NMOS transistor as the driving transistor with BiCMOS inverters is proposed, and its highspeed operation is confirmed. Next, a multiplexer which selects a pair of bit‐lines by switching the pull‐up voltage with an NMOS transistor and drives data‐lines with emitter‐follower circuits is proposed and its high‐speed operation confirmed. Finally, an optimized memory cell array configuration that minimizes the delay time from the memory cell to the mult

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractBased on the fact that the magnetostatic mode in a YIG thin film depends on the direction of a dc magnetic field, a frequency‐controllable oscillator is proposed. First, the dispersion and delay characteristics are analyzed theoretically for the magnetostatic wave in a YIG thin film magnetized in an arbitrary angle. Especially the delay characteristics have been analyzed both in terms of the group delay and the phase delay, and correlated with the oscillation frequency. Next, on both sides of a YIG thin film with a thickness of 13.6 μm and a size of 5 × 15 mm2, ten metal strips are evaporated at a pitch of 1 mm. The filtering characteristics of this Bragg reflection filter are then evaluated. Subsequently, this filter and an FET amplifier are combined to form an oscillator for 2 to 4 GHz. Measured results for the oscillation characteristics, output power and spectrum for different magnetic field directions are compared with theoretical results. Finally, as an application of this oscillator, a correlator is proposed and its operation is explai

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis paper investigates the relative effectiveness of three different definitions of mode‐field diameter in evaluation of splice losses of current and dispersion‐shifted fibers. As a result, it is shown that the difference in splice losses, due to various definitions, increases with decreasingVvalue. Further, it is confirmed theoretically and experimentally that by using Petermann's new definition, it is possible to estimate the splice loss very well. Next, using NFP and FFP methods, the measurement conditions of mode field diameter are also investigated. As a result, it is shown theoretically and experimentally that to keep the measurement error below 1 percent, it is necessary for the dynamic ranges of NFP and FFP methods to be larger than 25 and 35 dB, respectively. Under these conditions, it is shown that the measured results of both methods are in good agreem

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA metal‐clad optical waveguide can be used as a polarizer which passes the TE mode but blocks the TM mode. Numerous studies have been reported on metal loaded on slab waveguides. However, little has been reported on practical three‐dimensional waveguides. In this paper, a multilayered guided polarizer is fabricated by loading an AL film on a polymer thin‐film waveguide via a low‐index buffer layer. The polarization characteristics have been studied. In the case of a slab waveguide, the extinction of ratio of the guided wave intensities of the TE and TM modes increases with the film thickness of the buffer layer. It becomes a maximum of 34 dB for a film thickness of 0.18 μm and then decreases gradually. In the case of three‐dimensional waveguide, the electric field distribution of the hybrid guided mode is a mixture of the TE and TM modes. Hence, the extinction ratio is somewhat lower. However, the buffer layer thickness dependence of the extinction ratio is about the same as the one in the slabe waveguide. In the case of waveguide widths of 50 and 5 μm, the extinction ratio of the polarizer has been 30 and 22 dB, respectively, for a buffer layer thickness

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA multi‐quantum barrier (MQB) is proposed which is made of super lattices. The electron wave reflectivity and the leakage current of the MQB structure for an electron energy are calculated theoretically by means of a simplified model. The MQB structure studied here is a multiple heterostructure made of a combination of periodic structures with different well widths and barrier widths. The reflected waves from each interface are intensified by interference. The energy values at which the reflection is intensified are changed slightly by changing periodic structures. By combining these periodic structures the reflectivity is enhanced toward unity up to the energy higher than the classical barrier height. It is found from the calculations that the effective potential height of the MQB structure is higher by about 30 percent in the GaAs/AlAs and by about 50 percent in the Ga0.47In0.53As/InP than the classical barrier height. It is expected that the MQB structure can be used in high‐temperature operation light‐emitting devices and short‐wavelength light‐emittin

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA numerical analysis based on the Monte Carlo simulation has been carried out for the space‐charge effect affecting the longitudinal energy broadening of the electron beams. The collisions of the electrons are treated as a many‐body problem. For (1) a cross‐over model, and (2) a triode electrode gun model, the electron beam current dependence of the energy distribution and the current density distribution is studied. It is found that the anomalous energy broadening that has not been explained fully by the existing theoretical analysis based on the two‐body problem approximation can now be understood quantitatively. The validity of our analysis method is thus demon

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA hot‐carrier simulator (H2‐CAST) is developed using the “effective electron temperature model;” and with this simulator, the LDD structure is analyzed. This simulator is based on a 3‐D device simulator, where the carrier motion in the oxide film is also considered. The model equation for the channel hot electron region and the avalanche hot electron region in the NMOS single‐drain structure is evaluated. It is found that the model is valid for an analysis of the hot‐carrier injection phenomena in both regions. From the analysis of the LDD structure, it is apparent that the injection of the avalanche hot‐holes is responsible for the degradation of the device characteristic. This simulator is considered to be an effective tool in designing a device with an effective channel lengthLeffl

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractRadiation effects in SiO2/Si structures are studied by capacitance‐voltage characteristics of MOS diodes. As a radiation, X‐ray is used mainly because it can be shielded easier than γ‐ray from Co 60. Although the two radiations have different photon energy, it is found that they cause the same effects in device characteristics. Therefore, X‐ray is thought to be suitable for irradiation tests of devices. Both the positive fixed charge in the SiO2film and the SiO2/Si interface states caused by X‐ray irradiation are strongly dependent on the polarity of a bias voltage applied to a metal gate of an MOS diode during irradiation. When the polarity is positive, the radiation effects are several times stronger than those when the polarity is negative. These results are considered to indicate that both the positive fixed charges and the interface states are not generated directly by X‐ray photons, but generated by mobile positive charges created in the SiO2film due to the irradiation. In addition, dependence of the radiation effects on device fabrication processes is studied. For example, it is found that when thermal oxidation is carried out in ambient‐containing impurities such as chlorine and nitrogen, the radiation effects in the SiO2/Si structures become more severe. These results indicate that the suitable selection of device fabrication processes will lead to a better radiation hardness

ISSN:8756-663X    

DOI:10.1002/ecjb.4420710510

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY