摘要:

AbstractIn this paper, the formulation of the analysis based on the finite element method is presented for the first time for an anisotropic dielectric grating. By this analysis method, the diffraction characteristics of a plane wave by an anisotropic dielectric grating with an arbitrary shape can be computed easily. The finite element method is applied to the region corresponding to one period containing an anisotropic dielectric grating. The analytical relationships are applied to the boundaries on the incident and transmitted sides while the periodic boundary condition is applied to all other boundaries. Specifically, an index modulated grating and a groove grating are chosen for the analysis of the diffraction characteristics when the TE and TM waves are coupled. From the comparison with the analysis results by the coupled‐mode theory and the spatial harmonic expansion method, the validity of the present method is confirme

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790101

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

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper presents a method for recovering, by using the iterative Fourier‐transform algorithm, the complex amplitude transmittance of a recorded one‐dimensional Fourier transform‐type kinoform. A method for estimating the phase‐recording characteristic of the kinoform fabrication system by comparing the retrieved phase with the theoretical phase is also presented. The spatial variations of both the magnitude and phase inside each of the kinoform cells were evaluated to improve estimation of the phase‐recording characteristic. The initial estimate of the kinoform phase given to the algorithm was derived using the knowledge that the recorded phase is an approximation of the phase to be recorded.The relationship between the shift of the central sampling point of the Fourier image from the optical axis and the retrieved phase of the kinoform is investigated; a kinoform phase pattern with a structure suitable for indirectly detecting the shift is then proposed. In an experiment using a kinoform fabrication system including a photographic process, the recorded phase distribution is retrieved at five sampling points of each cell. The phase‐recording characteristic is estimated using the retrieved phase values.Next, a computer simulation is executed to reveal the influence of errors in the measurement of magnitude. The simulation result shows that the recorded phase distribution can approximately be retrieved when the rms error added to the magnitude is approximately 10 percent of its average. Furthermore, the validity of the phase distribution retrieved in the experiment i

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790102

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

年代:1996

数据来源: WILEY

摘要:

AbstractA new procedure for the optimum design of optoelectronic devices is explained in this paper and an automatic search is made simultaneously for the structure satisfying various demands. The feature of this procedure is in the introduction of cost by which the quantitative evaluation of the structure becomes possible and the global search for the required structure by simulated annealing can be carried out.First, the definition of cost and details of the optimization procedure are clarified. In optimization, in addition to convergence to the minimum point of the cost function (the optimum configuration from theoretical viewpoint), the convergence also is possible in structures with great tolerance to fabrication errors (neighborhood cost (NC) and finite temperature annealing (FTA) methods).Next, these three proposed methods are used in the design of a pnpn differential optical switch and the effectiveness of the methods is verified. The method of cost expression, the relation between annealing parameters, and convergence are investigated. It is shown that cost expression with large degree of freedom improves the search for high‐performance structures and the initial temperature of annealing or the fixed temperature of FTA method is the important parameter which sets up the probability of acceptance. Further, it is shown that the convergence cost is inversely proportional to the time spent in annealing. These results are useful guidelines in the optimum design of arbitrary optoelectronic device

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790103

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

年代:1996

数据来源: WILEY

摘要:

AbstractAccelerated tests of Er‐doped fibers in hydrogen environments are carried out and as the evidence of their long‐term utilization, the degradations in loss and gain are estimated. The hydrogen‐induced loss‐increase in Er‐doped fibers with 0 to 3 percent aluminum (Al) content is formulated. As the results of quantitative investigations, it is understood that during 25 years of use, there is almost no transmission loss increase in 1.55 μm wavelength region and at hydrogen partial pressure of 0.001 atm and 40°C if there is no Al content.In case of 1 wt% Al content, the loss increase is 0.04 dB/20 m while it is 0.08 dB/20 m if the Al content is 3 wt%. Further, it is possible to describe the gain degradations, under hydrogen environment, by the increase of background losses. Under the forementioned conditions, the gain degradation is estimated to be 0.07 dB if the Al content is 1 wt% and 0.15 dB if the content is 3 wt%. Therefore, it becomes clear that their characteristics are immune to hydrogen environment in real a

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790104

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

年代:1996

数据来源: WILEY

摘要:

AbstractTo evaluate the accuracy of the effective channel‐length extraction method, the behavior of the measurement errors in the least‐square method, used twice in the extraction procedure, is studied. It is found that the increased number of data are mainly effective in suppressing the dispersion of the measurement data; these data are also somewhat effective in reducing the actual measurement errors. Based on this result, the actual effective channel‐length extraction using experimental MOSFET data is studied. It is observed in the samples used here that the linear relation between total MOSFET resistance and design channel length changes in short channel region. It is found in such a case that as many reference MOSFETs as possible, including both short and long MOSFETs, should be

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790105

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

年代:1996

数据来源: WILEY

摘要:

AbstractWhen a switched capacitor circuit is constructed, a provision for output offset voltage generation by the effect of the clock feedthrough charge is indispensable. Especially in the circuit made of individual components using commercially available analog switches, this effect is significant.In this paper, the generation mechanism of the feedthrough charge in an analog switch is analyzed and a circuit configuration method is proposed for compensation of the feedthrough effect for the integrator as the most fundamental switched capacitor circuit. Also, by a comparison experiment, with the conventional method, the effectiveness of the proposed circuit is confirmed.The circuit size is larger as an integrator itself than the one by the conventional method. However, even in the case with a multiple cascading of the integrators such as in a higher‐order filter, the feedthrough compensation is possible with only one feedback loop so that the overhead for the increased circuit size can be reduced. According to the trial circuit, the output offset voltage can be suppressed to the level of several millivolts. Hence, the present method can be applied to various operating circuits with high accurac

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790106

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe relationship between the device property under drain‐source breakdown and device structure parameters of insulated gate bipolar transistors was simulated. Then the following facts were revealed: 1) the impurity concentration in the n−drain layer and the layer thickness determine the breakdown mode. One such mode is the avalanche‐suppressed punch‐through mode proposed by the authors, where the depletion layer in the n−drain layer reaches the p+drain substrate and breakdown is caused by the hole injection from the p+drain substrate to the n−drain layer. Another mode is the nonpunch‐through mode, where avalanche takes place in the neighborhood of the junction between the p body layer and n−drain layer, causing breakdown; 2) the breakdown energy spreads more and the hot carrier concentration near the device surface is lower in the avalanche‐suppressed insulated gate bipolar transistor than in the nonpunch‐through insulated gate bipolar transistor. As a result, the breakdown resistance of the former transistor is higher than that of the latter transistor; and 3) it was found that the breakdown voltage is more stable against the changes in the drain current and temperature in the former transistor than in the latter transistor. It was found also that the former transistor has a higher surge energy endurance than th

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790107

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

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper reports on recent improvements in organic spin‐on glass (SOG) planarization technology combined with etch‐back process. A general rule has been established for SOG planarization mechanism that is suitable for every kind of wiring pattern distribution. This general rule, the volume constant rule, shows that the SOG volume in a certain projection length along the horizontal direction is constant and independent of the wiring width. Based on this rule, it is found that the SOG planarization process margin can be increased significantly by decreasing the plasma SiO2(= P‐SiO2) layer thickness underneath the SOG layer.The characteristics of this newly developed organic SOG material have been investigated. This new organic SOG material developed by Hitachi Chemical Company, Ltd. (HSG‐2209S‐R7) has heat reflow capability that causes the movement of SOG on the wires to the space during the second baking; this results in improvements in local planarization and decrease in the SOG thickness on the wires.A six‐level metallization test structure for a logic LSI has been successfully created using the optimized process

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790108

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

年代:1996

数据来源: WILEY

摘要:

AbstractThe reaction mechanism of blanket chemical vapor deposition of WSixfrom WF6/Si2H6mixture was modeled based on the data of a tubular reactor. In this reaction, film deposition is initiated by radical chain reaction and the silicon concentration in the film can be increased easily. The model is as follows. During radical chain reaction, reaction between WF6and Si2H6takes place, Si‐rich intermediary product with Si/W = 2 is formed and reaction between the product and Si2H6causes an increase of Si concentration. The Si concentration profile in the film in the reactor could be simulated by using the reaction speed constant as a fitting parameter and the validity of this model was confirmed. The activation energy of this reaction was 23.5 kJ/mol. Using this model, the Si concentration in the film formed in the substrate‐heating‐type reactor could be pred

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790109

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

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper describes a contact degradation mechanism during window formation followed by selective tungsten chemical vapor deposition (W‐CVD). Contact resistances by using selective W‐CVD were increased as the overetching rate increased. Surface analysis made it clear that the Si surface at the bottom of contact was damaged and oxygen atoms from dielectrics were introduced during window etching. These damage and oxygen atoms break Si‐Si bonds and make Si‐O bonds after additional ion implantation. The Si‐O bonds degrade the valence‐band density of states of the Si surface. Such a damaged surface will not react with WF6.This inactivation is the reason for contact degradation. Controlling the Si surface state by using the chemical dry etching (CDE) technique solves t

ISSN:8756-663X    

DOI:10.1002/ecjb.4420790110

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

年代:1996

数据来源: WILEY