A TlGaAs/GaAs multiple quantum-well (MQW) structure having four identical well layers was grown on a GaAs (001) substrate by low-temperature molecular-beam epitaxy (MBE) at 190. The (004) X-ray diffraction (XRD) curve of this sample showed satellite peaks up to the 3rd order at least. The measured XRD curve agreed well with the theoretically simulated one with a Tl content of x=7% and a width of 57 for the TlxGa1-xAs well layers. This result indicates that the grown MQW structure has good single-crystalline quality as well as flat and sharp interfaces.

This paper presents the design considerations for a digital dental X-ray system with a commercial CCD sensor. Especially the system should be able to work with several X-ray machines even with them for the classical film. The hardware-software co-design methodology is employed to optimize the system. The full digital implementation is assumed for the reliability of the system. The considered functions cover the pre-processing such as the exposure detection, clamping and the dark level correction and the post-processing such as gray level compensation. It is analyzed with some other constraints in order to make the final partition. The entire system based on the partition will be described.

We are developing a superconducting analog-to-digital converter (ADC) as a readout for high-resolution X-ray detectors based on a superconducting tunnel junction (STJ). The ADC has a sensitive front end which consists of a DC superconducting quantum interference device (SQUID). A signal current is digitized by this front end without using any preamplifiers. A single-flux-quantum (SFQ) pulse train whose frequency is proportional to the input current is launched by the front end, and integrated by a digital counter. The counter has a 10-bit resolution, and the integrated value is scanned and transferred to room-temperature processing modules with a frequency of 40 MHz. In this paper, the design of the ADC is described, and the preliminary results of the ADC performance test are shown. The performance of the STJ accompanied by the ADC is discussed in terms of the X-ray energy resolution.

Contact resistance of nickel hardened gold electroplate (NiHG) deposited on nickel-underplated phosphor bronze disk coupons (substrate) after thermal aging was measured with a hard gold-plated beryllium copper alloy pin probe by means of a four-point probe technique, compared to that of cobalt-hardened gold electroplate (CoHG). Surface of NiHG plated coupons after aging was analyzed by X-ray photoelectron spectroscopy (XPS) to investigate the influence of the oxide film formation during thermal aging on contact resistance of NiHG electroplate, compared to that of CoHG. Initial contact resistance of the NiHG coupons was less than 10 mΩ at a contact forces more than 0.05 N, increased to 10 mΩ at a contact force of 0.05 N after 100 hours aging at 200. In contrast, contact resistance of the CoHG coupons progressively increased with increase in aging time, reached 1000 mΩ even at a contact force of 0.05 N after 52 hours aging. XPS analysis for the NiHG coupons demonstrated that nickel oxide film was formed on the NiHG surface in conformity with parabolic growth kinetics, as cobalt oxide film formed on CoHG surface. However, a thickness of the latter film was approximately 4-fold larger than that of former after 100 hours aging at 200. The small increase in contact resistance of NiHG coupons after aging suggested to be due to inhibitory of nickel oxide film growth on the surface. The cause of relatively low and steady contact resistance of NiHG during thermal aging was discussed.

Recent advances in solid-state laser technology and ultrafast optics led to the generation of optical pulses as short as 5 femtoseconds with peak powers up to the subterawatt level from a compact kHz-repetition-rate all-solid-state laser. This source significantly pushes the frontiers of nonlinear optics. Exciting new possibilities include the investigation and exploitation of reversible nonlinear optical processes in solids at unprecedented intensity levels, the development of a compact laser-driven coherent soft-X ray source at photon energies near 1 keV, and the generation of attosecond xuv pulses. First, a brief review of recent milestones in the evolution of ultrafast laser technology is given, followed by a description of the high-power 5-fs source. The rest of the paper is devoted to applications in previously inaccessible regimes of nonlinear optics. We demonstrate that wide-gap dielectrics resist intensities in excess of 1014 W/cm2 in the sub-10 fs regime and the extension of high-harmonic generation in helium to wavelengths shorter than 2. 4 nm (Eph > 0. 5 keV).

In this article, a new type of diffusion template and an analogic CNN algorithm using this diffusion template for detecting some lung cancer symptoms in X-ray films are proposed. The performance of the diffusion template is investigated and our CNN algorithm is verified to detect some key lung cancer symptoms, successfully.

In this paper we propose a new medical image processing system called Virtualized Endoscope System (VES)", which can examine the inside of a virtualized human body. The virtualized human body is a 3-D digital image which is taken by such as X-ray CT scanner or MRI scanner. VES consists of three modules; (1) imaging, (2) segmentation and reconstruction and (3) interactive operation. The interactive operation module has following thee major functions; (a) display of, (b) measurement from, and (c) manipulation to the virtualized human body. The user of the system can observe freely both the inside and the outside of a target organ from any point and any direction freely, and can perform necessary measurement interactively concerning angle and length at any time during observation. VES enables to observe repeatedly an area where the real endoscope can not enter without pain from any direction which the real endoscope can not. We applied this system to real 3-D X-ray CT images and obtained good result.

A new anti-static technology to neutralize static electricity by high energy photon irradiation has been developed. Ions and electrons required for neutralization are generated by ionization of gas molecules in the vicinity of a charged substance. Gas molecules absorbs photons to become ionized. The wavelength chosen for the irradiation depends on the neutralization atmosphere. Soft X-rays with wavelength over about 1 are effective in air or O2 gas at pressure higher than several hundreds Torr. Vacuum UV-rays with wavelength below about 1350 is effective in N2 gas, Ar gas, or reduced pressure ambients. These methods feature excellent neutralization capa-bility. Electrostatic potential can be reduced to 0 V in a very short time without encountering the problems of which conven-tional corona discharge ionizers.

We have studied in detail the effect of gas flow rates on the film properties of low-temperature (300) polycrystalline silicon (poly-Si) films prepared by conventional plasma enhanced chemical vapor deposition (13.56 MHz) with SiF4/SiH4/H2 gases. The effect of SiH4 flow rate on crystallization is shown to be large. A small amount of SiH4 with high SiF4 and H2 flow rates (50[H2]/[SiH4]1200, 20[SiF4]/[SiH4]150, 1[H2]/[SiF4]16) is important to form poly-Si films. The poly-Si films deposited under such optimized conditions had shown preferential 〈110〉-orientation and the crystalline fraction is estimated to be more than 80%. The deposition rates are in the range of 5-30 nm/min. The conductivity is in the range of 10-8-10-6 S/cm. Further, the electrical conduction indicates an activation type, and the activation energy is in the range of 0.5-0.6 eV.

A 0.25-µm BiCMOS technology has been developed using three sophisticated technologies; the HSST/BiCMOS device, synchrotron orbital radiation (SOR) X-ray lithography, and an advanced two-level metallization. The HSST/BiCMOS provides a 25.4-ps double-poly bipolar device using High-performance Super Self-Aligned Process Technology (HSST), and a 42 ps/2 V CMOS inverter. SOR lithography allows a 0.18 µm gate and 0.2 µm via-hole patternings by using single-level resists. The metallization process features a new planarization technique of the 0.3-µm first wire, and a selective CVD aluminum plug for a 0.25 µm via-hole with contact resistance lower than 1Ω. These 0.25-µm technologies are used to successfully fabricate a 4 KG 0.25 µm CMOS gate-array LSI on a BiCMOS test chip of 12 mm square, which operates at 58 ps/G at 2 V. This result demonstrates that SOR lithography will pave the way for the fabrication of sub-0.25-µm BiCMOS ULSIs.

Directional dry etching of Tantalum is described X-ray lithography absorber patterns. Experiments are carried out using both reactive ion etching in CBrF3-based plasma and electron-cyclotron-resonance ion-stream etching in Cl2-based plasma. Ta absorber patterns with perpendicular sidewalls cannot be obtained by RIE when only CBrF3 gas is used as the etchant. While adding CH4 to CBrF3 effectively improves the undercutting of Ta patterns, it deteriorates etching stability because of the intensive deposition effect of CH4 fractions. By adding an Ar/CH4 mixture gas to CBrF3, it is possible to use RIE to fabricate 0.2-µm Ta absorber patterns with perpendicular sidewalls. ECR ion-stream etching is investigated to obtain high etching selectivity between Ta and SiO2 (etching mask)/SiN (membrane). Adding O2 to the Cl2 etchant improves undercutting without remarkably decreasing etching selectivity. Furthermore, an ECR ion-stream etching method is developed to stably etch Ta absorber patterns finer than 0.2µm. This is successfully applied to X-ray lithography mask fabrication for LSI test devices.

Hot carrier reliability due to residual damage in the gate oxide created by synchrotron X-ray irradiation is investigated for subquarter-micrometer NMOSFETs under a wide irradiation-dose range (103,000 mJ/cm2). Although irradiation-induced interface-traps and positive charges are completely eliminated after 400 post-metalization-annealing, neutral electron traps partially remain. The effects of the residual trapa on hot-carrier degradation can be negligible when gate oxides thinner than about 5 nm are used, and it is found that there is no effect of irradiation damage on interface-trap generation due to injected hot-carriers. It is concluded that the influence of synchrotron radiation X-ray lithography on hot-carrier-induced degradation in subquarter-micrometer NMOSFETs can be negligible.

The minimum transferable linewidth by X-ray is derived using waveguide analysis. The minimum width is determined by the refractive index of the absorber and does not depend on the X-ray wavelength. Therefore there is an optimum mask aperture size which provides the minimum linewidth. By using Au as the absorber, 8 nm linewidth is attainable.