Magnetotransport characterization of surface-treated InP/InGaAs heterojunction bipolar transistors

The results of surface modification induced effects on InP/InGaAs single heterojunction bipolar transistors, as revealed by magnetotransport experiments, are described here. The surface treatments included both sulphur-based surface passivation and ion bombardment-induced surface damage. The former is known to improve device characteristics and the latter to degrade device operation. In this work the aim was to assess these techniques for tailoring device performance for surface sensing applications. Device characteristics were found to be sensitive to surface preparation prior to measurements. Measurements revealed that surface treatments that improve device performance also reduce sensitivity to external magnetic fields while treatments that degrade performance make devices more sensitive to externally applied magnetic fields.     

CMOS磁敏器件的两维数值模拟

本文在IBM-PC计算机上,数值模拟了线性区CMOS磁敏器件,即对垂直于器件表面磁场敏感的劈裂漏极MOSFET,并将其推广到饱和区。针对器件的矩形结构,采用非均匀矩形网格有限差分方法求解了在磁场存在下载流子的输运方程,给出了电压分布,且分析了灵敏度和线性度。计算结果与实验相符。     

A model and equivalent circuit for a superconducting flux flowtransistor

A three-terminal high-frequency active device made of a single film of a high T_c superconductor that is based on the magnetic control of flux flow is presented. The device is composed of parallel weak links with a nearby magnetic control line. A model has been developed that is based on solving the equation of motion of Abrikosov vortices subject to Lorentz viscous and pinning forces, as well as magnetic surface barriers. The model has been used to predict device transit time (computed from flux velocity) and device I- V curves. The predictions are compared to measured parameters with resulting very good agreement     

新型等离子体源及其应用

为适应半导体技术的快速发展,需要寻求一些新的等离子体源。介绍了两种比较新颖的等离子体源———表面波等离子体(SWP,surface wave plasma)和磁中性环路放电等离子体(NLD,mag-netic neutral loop discharge)。前者的设备没有磁场,且结构简单,工作温度低,易于大面积化;而后者的设备可以通过改变其中性环路直径方便地产生各种形状的等离子体,可用于高深宽比刻蚀,也可用于大面积刻蚀。与传统等离子体源相比,它们具有明显的优势,有望成为下一代等离子体源。     

Hybrid magnetic tunnel junction/vertical cavity surface emittinglaser field sensor device

A hybrid magneto-optoelectronic device is demonstrated, composed of a magnetic tunnel junction and a vertical cavity surface emitting diode laser. External magnetic field changes are translated into amplitude modulation of the laser output power with sensitivity that suggests applications in wireless and remote sensing of magnetic fields     

The vertical hall-effect device

A novel device, sensitive to the magnetic field parallel to the chip surface is described. The device has a form remeniscent of a semi circular plate placed perpendicularly to the chip plane. The operation principle is that of the conventional Hall-effect device. The unusual geometry principally does not affect sensitivity. The experimental samples are fabricated using a standard bulk CMOS technology, where the p-well deep diffusion is used to surround the active device volume. Sensitivity up to 450 V/AT is measured.     

Robust control of a planar manipulator for flexible and contactless handling

Many industries require non-contact and flexible manipulation systems, such as magnetic or pneumatic devices. In this paper, we describe a one-degree-of-freedom position control of an induced-air flow surface. This device allows to convey objects on an air cushion using an original aerodynamic traction principle. A model of the system is established and the parameters are identified experimentally. A H_∞ robust controller is designed and implemented on the device in order to control the object position. Experiments with objects of various dimensions and materials are conducted and showed the robustness capabilities of the controller.     

ZnS对HgCdTe器件的表面覆盖及其输运特性的影响

利用成熟的ＨｇＣｄＴｅ器件生产工艺制备了ＨｇＣｄＴｅＨａｌｌ器件,利用Ａｒ束溅射沉积技术在ＨｇＣｄＴｅＨａｌｌ器件表面实现了ＺｎＳ介质薄膜的代温生长;用低浊变磁场Ｈｌｌ测量技术对ＺｎＳ薄膜覆盖前后的Ｈａｌｌ器件输运特性进行了研究,分析了ＺｎＳ薄膜的沉积生长对器件中ＨｇＣｄＴｅ晶体表面、体内载流子的分布、迁移率的影响。实验证明,利用文中的Ａｒ＾＋束溅射沉积技术在ＨｇＣｄＴｅ器件表面进行ＺｎＳ介质膜生     

Microwave Delay Techniques Using YIG

Recent developments in microwave delay techniques employing single-crystal yttrium iron gamet (YIG) are described. In particular, the operation of a two-port, electronically variable-delay device utilizing long-wavelength spin-wave propagation in single-crystal YIG is presented in detail. Specific advantages of this device are transmission-type operation, delay continuously variable from zero to several microseconds by means of magnetic field, and lack of critical dimensions or surface finishes. This form of delay, as well as those due to acoustic-wave and spin-wave/acoustic-wave propagation, have been observed at frequencies from 1 to 10 Gc/s. A comparison of the performances of these delay processes is made, with special attention to insertion loss, bandwidth, frequency limits, and variable-delay range.     

The BNR diode, a current-controlled negative-resistance device

The bonded NR (negative-resistance) diode is a current-controlled negative-resistance device, fabricated in a similar manner as conventional gold-bonded diodes. Switching times of the device are a few nanoseconds. The I-V characteristic can be strongly controlled by magnetic fields and by illumination. Under continuous operation, magnetic sensitivity(partial V/partial B)_{I}up to about 2.7 mv/gauss was observed under dc conditions, decreasing exponentially in an ac magnetic field above 2-3 kc, and disappearing around 25 kc. The sensitivity of the turnover voltage to illumination at a wavelength of 1.4 µ was found to be of the order of 10 mv/µW. The electrical and optical characteristics can be explained on the basis of Gunn's avalanche injection model. The magnetic sensitivity and an effect of the diode length on its I-V characteristics are compatible with lifetime modulation in the bulk material. Possible applications of the device as a magnetic and optical sensor are discussed, and an analysis of the device as an active circuit element utilizing its negative resistance is presented.     

A silicon MOS magnetic field transducer of high sensitivity

A structure has been devised which converts magnetic flux density change to a change in output current. The structure is essentially a P-channel MOST with the drain diffusion split into two halves. A magnetic field normal to the silicon surface deflects device current towards one half-drain. By operating the MOST in the "pinched-off" mode (VDS> VGS-VT) the output impedance is made high, so that large output voltage swings may be obtained. A theoretical study of the voltage and current distributions in the MOST channel has given data on the influence of device geometry on sensitivity. Experimental results indicate a linear relationship between output current and magnetic flux density, and an unexplained nonlinear variation of output with device current. Comparison of experimental results with theory indicates a carrier Hall mobility in the channel of 116 cm²/V.s.     

An integrated silicon magnetic field sensor using the magnetodiode principle

We report a novel integrated magnetic field sensitive device. Its structure is reminiscent of the bipolar transistor, but its operation is essentially that of a magnetodiode: a reverse-biased p-n (collector) junction plays a role similar to that of the high recombining surface of classical magnetodiodes. The device can be manufactured in standard bulk CMOS or bipolar technology. Sensitivity up to 25 V/T at 10-mA current is achieved. Voltage-current characteristics shows saturation and negative resistance regions, which are explained by JFET and UJT effects, respectively.     

Selective alignment of a ZnO nanowire in a magnetic field for the fabrication of an air-gap field-effect transistor

An air-gap field-effect transistor (FET) was prepared by selectively aligning a Ni-capped ZnO nanowire in a magnetic field on a pre-fabricated electrode patterns formed by lithography. It was demonstrated that the magnetic alignment technique could be applied effectively to the fabrication of air-gap nanowire FETs with desired circuit configurations. This device showed operational characteristic strongly dependent on the possible surface adsorbates originating from the negatively charged oxygen related species, as compared to the back-gate nanowire FET separately prepared for comparison. These results will illuminate the prospect of realizing producible matrix-type devices based on one-dimensional nanostructures such as logic circuits and biochemical sensors.     

Analysis of a Buried Layer Millimeter-Wave Phase Shifter (Short Paper)

The results of an analysis of an optically controlled millimeter-wave phase shifter are presented. The phase shift is obtained when electron-hole pairs are created in a thin region in the interior of a semiconductor waveguide. The device exhibits maximum phase shifts for the transverse electric mode. This behavior is different from phase shifters using surface excitation, which give maximum phase shifts for the transverse magnetic mode. The new configuration gives higher phase shifts per decibel attenuation than devices employing surface excitation.     

Active Regulation of On‐Demand Drug Delivery by Magnetically Triggerable Microspouters

Triggerable devices capable of on‐demand, controlled release of therapeutics are attractive options for the treatment of local diseases because of their potential to enhance therapeutic effectiveness with reduced systemic toxicity. Here, the design and fabrication of a miniaturized device, termed a microspouter, is described. This device is shown to provide active and precise control of localized delivery of drugs on demand. The microspouter is composed of a magnetic sponge to provide the force for drug release through magnetic field‐induced reversible deformation, a reservoir for the sponge installation and drug loading, and a soft membrane for sealing the device. Following application of a magnetic field to the microspouter, the shrinking of the sponge may trigger a spouting of drug through a membrane's microaperture. The efficiency of the device in controlling the dose and time course of drug release under different external magnetic fields has been demonstrated using methylene blue and docetaxel as model drugs. Additionally, the microspouter is found to have low background drug leakage that allows for tunable drug release in an ex vivo implantation experiment. All the results confirm the microspouter as a potential device for safe, long‐time, and controlled drug release in local disease treatment.     

GMM和SAW谐振器复合磁传感器设计与分析

提出了一种新的超磁致伸缩材料(GMM)和声表面波(SAW)谐振器构成的复合磁传感器,将磁场中GMM的应力应变传递到SAW谐振器上,改变其谐振频率,检测谐振频率进行磁场测量。推导了复合磁传感器在磁场中的频率响应及磁场-频率偏移量关系,并对传感器的静态特性进行了测试。分析表明该传感器为低通系统,截止频率约为14.34Hz。实验验证了复合传感器的最高静态灵敏度可达到190Hz/Oe。     

A High-Temperature Superconducting Magnetic Transmission Device

A high-temperature superconducting (HTS) magnetic transmission device is introduced. The key part of the transmission device is an HTS magnetic helix transmission mechanism, which consists of a magnetic bolt and an HTS nut, and its strong points are being frictionless and having high efficiency. The transport platform is driven along the direction of the magnetic bolt. All moving parts of the device do not come into contact with the load that is transported by the transport platform. The basic mechanical properties of this device are studied. The position precision and angle precision of the transport platform are discussed.     

自适应双参考磁场梯度探测原理

本文使用4个单分量磁探头构成双参考磁场梯度探测装置.4个探头组成3个磁场梯度传感器,其中一个为信号传感器,另两个为噪声传感器.以信号传感器输出作为原始输入,噪声传感器输出作为参考输入,采用自适应噪声抵消技术,能有效消除因载体运动产生的涡流磁场及因磁探头方向相对地磁方向改变而引起的噪声输出.本文提出的双参考磁场梯度探测装置具有工艺性好,灵敏度高,虚警概率低的优点,可在实际磁探系统中使用.     

An automated loading and unloading system for a maglev wafertransport path

An automated loading and unloading system for placing silicon wafers on a carrier is discussed. Interest is particularly focused on the automated loading of wafers onto a carrier which is moved along a transport path using a magnetic levitation (maglev) drive mechanism. The system consists of a wafer carrier which can move along the path and is purely passive, and a loading and unloading device which uses vacuum and electrical power. A magnetic clamping mechanism presents the wafer from sliding when the carrier moves along the path. The electromagnetic loading and unloading device firmly holds the wafer using vacuum suction and may be carried out by a robot. Only the bottom surface and edge of the wafer are touched by the carrier and the loader-unloader. The loader-unloader described, when combined with a maglev transport path, is potentially useful for connecting the processing tools in a cluster or connecting the workstations along a semiconductor fabrication line     

微型磁瓦表面线缺陷视觉检测方法研究

针对微型磁瓦图像对比度低、纹理背景复杂、亮 度不均匀、缺陷区域小等特点,本文提出了一种微 型磁瓦表面线缺陷视觉检测方法。首先,构造自适应静态掩膜,屏蔽微型磁瓦轮廓;其次, 采用非线性各 向异性扩散方程,抑制微型磁瓦表面纹理;进而,构造动态掩膜自下而上扫描磁瓦图像,提 取线缺陷区域; 最后,在开发的微型磁瓦视觉检测实验装置上,进行了大量的实验研究。实验结果表明,本 文缺陷提取算 法能够较准确提取出磁瓦表面图像的线缺陷,表面缺陷检测的准确率为94.6%。