变容管 S 波段直接调相器

引言通过变容二极管的结电容随其两端的外加电压而变化,已使该变容二极管应用于微波移相器中。在移相器的这些应用中,可以得到一个随外加电压而变化的相当大的相移。由于相移与电压成非线性关系,因此,要求相角随     

硅调谐变容二极管的特性

<正> 变容二极管是指它的端电容按一定的方式随反向偏压而变化的一种半导体二极管。调谐变容二极管的电容—电压特性适用于调谐电路(如在电调谐器UHF和VHF频段中作调谐用),其特点是串联谐振频率和截止频率远高于使用频率。现以无锡元件四厂生产用于C型电调谐器的2CC32型调谐变容二极管为例,介绍其有关特性。     

磁控溅射制备Co／Al2O3／FeNi磁隧道结

利用磁控溅射设备和光刻技术，采用金属等离子体氧化法，设计制作了10μm×15μm的Co／Al2O3／FeNi磁隧道结，并在77K下对其输运特性进行了研究。测得了11％的隧道磁电阻。随着外加电压增加，隧道结的磁电阻单调减小。测量了样品的I-V特性曲线，发现随着外加电压的增加，曲线逐渐偏离线性，电阻变小，这与理论相符合。电阻随温度变化曲线表明电阻随温度升高而减小，而且在210K处有一个拐点。表现出典型的隧穿过程的特征。     

Q博士考考你

单项选择题1、对于稳压二极管,它正常工作时是处于()状态。A、正向导通B、反向击穿C、截止D、随外加电压变化而变化2、放大电路在高频区放大倍数下降的原因是()A、耦合电容和旁路电容等大电容的影响B、晶体管极间电容和分布电容等小电容的影响C、晶体管的非线性特性D、放大电路     

负性VA-LCD视角特性研究

液晶材料具有双折射效应,因此偏振光在液晶材料中各个方向上发生双折射的程度不同,这决定了LCD的视角特性和对比度随视角的变化有所不同。用光栅光谱仪测量在不同电压驱动下负性VA-LCD的电光特性,以及测量其电光特性随视角的变化;并对其三基色的电光特性和视角特性进行分析。结果表明,三基色的透过率在驱动电压2.2 V之前很小;在2.2 V后,透过率随电压的升高而增大;其中红基色和绿基色的透过率是一直升高,在电压达到5.0 V后,就是趋于平缓,而蓝基色的透过率是在3.7 V左右达到最大,而后慢慢变小,最后在电压达到6.0 V后,趋近一个稳定值。负性VA-LCD三基色的视角特性:红基色的视角范围最宽,绿基色次之,蓝基色的视角范围最窄。     

超结与浮结型肖特基势垒二极管的比较研究

对浮结型及超结型肖特基势垒二极管静态及动态特性进行了解析及模拟.静态特性通过解析击穿电压与导通电阻之间的关系得到.反向恢复特性通过二极管电容随反向电压变化关系解释,商用混合模拟器MEDICI模拟结果表明浮结结构具有软恢复特性,软度因子为0.949.超结结构恢复特性较硬,软度因子为0.7807.当考虑这两种耐压结构时,必...     

小巧长寿的变容二极管

变容二极管又称“可变电抗二极管”．它利用半导体PN结电容或金属一半导体接触势垒电容随外加反向偏压变化而变化的原理制成,是一种专门作为“压控可变电容器”的特殊晶体二极管。变容二极管通常可替代可变电容器,在现代通信设备及家用电器中做高频调谐、频率自动微调、扫描振荡及相位控制等使用。     

电视机用硅二极管的测试

功率硅二极管在各种电视机中用作整流管、升压管、阻尼管、续流二极管等,这些管子往往承受较高的电压,流过的电流也比较大,使用数量又多,故应注意其可靠性。正向及反向伏安特性硅二极管的正向及反向伏安特性可在晶体管特性图示仪上测绘。当正向电压逐渐增大超过 V_c 时,正向电流 I_F 随电压迅速上升,当环境温度自 t_1升高到t_2时,特性变化如图1所示。在晶体管特性图示仪上可观察到室温时硅二极管的反向特性大致如图2中 t_1情况所示。当逐步提高反向电压 V_R 到雪崩电压 V_(?)以上时,反向电流 I_R 迅速上升,当环境温度自 t_1上升到 t_2时,雪崩电压升高到 V′_(?),温度继续上升到 t_3时,反向特性形状发生变     

锁模激光照射下InGaAs p-i-n管的负电压响应机理

在考察InGaAs p-i-n管对锁模激光响应的实验中,发现其响应电压在经历一个快速的上升沿和缓慢的拖尾以后有一个明显的负电压.在二极管的线性响应阶段,负电压与正电压的峰值之比大约在0.18左右,且不随激光脉冲能量的增大而改变;在二极管的非线性响应阶段,随着光脉冲能量的增大,负电压逐渐变小最终消失.通过对p-in管的等效电路模型的建立以及对RLC振荡电路方程的求解,认为负电压的产生是由于二极管表现出了可观的电感特性,而负电压的消失是由于二极管的结电容随着光脉冲能量增大而增大的结果.该研究结果对InGaAs p-i-n管的设计和制造具有一定的理论指导作用.     

怎样控制电源电压随温度变化的关系

随着我国电子技术的发展,各种新的器件不断涌现,有些器件在一定的条件下对电源的要求也不断提高.例如,我厂研制的砷化镓激光云高仪,其接收部分(如图1)的探头——硅光电雪崩二极管D,要求电源电压随温度变化的曲线与它的击穿电压(雪崩点)随温度变化的特性曲线同步,如图2.图中曲线①为雪崩管的击穿电压随温度变化的特性曲线,曲线②为普通稳压源的电压随温度变化的曲线,曲线③为具有温度补偿     

有源集成天线的谐波平衡法分析

本文首先利用矩量法计算平面馈电型微带贴片天线的输入阻抗,并对其进行实验测量;其次,使用谐波平衡法分析了以Ｃｕｎｎ管为振荡源的有源微带天线电路。在求解谐波平衡方程时采用Ｐｏｗｅｌｌ优化法,得出整体电路的振荡频率和振荡电压;再次,仍使用谐波平衡法对肖特基二极管与微带贴片天线集成的接收型有源天线进行大信号的小信号分析,同样经过优化,得出其在本振电压作用下,非线性部分的谐波电压以及在小信号电压作用下的变频     

Transition voltage of AlGaN/GaN heterostructure MSM varactor with two-dimensional electron gas

It is not in principle clear which of the capacitors forming a varactor is responsible for the capacitance change at the transition voltage. We analyzed a theoretical case of transition voltage of the varactor formed by ideal Schottky diodes. Since real devices often do not behave strictly according to thermionic theory we also analyzed the transition voltage of experimental metal-semiconductor-metal (MSM) varactor with a two-dimensional electron gas and an MSM varactor with a dielectric layer. We found that the transition voltage of the MSM varactor was determined by the reverse-biased diode of the varactor. A voltage drop on the forward-biased diode was too low to spill over electrons in the AlGaN layer and to reduce the capacitance of the structure. The transition voltage of the MSM varactor was therefore very close to – the threshold voltage of the single diode. The situation was different with the MSM varactor with higher leakage current or in MSM varactor with the dielectric layer. The voltage drop on the forward-biased diode is no more negligible and both parts of the varactor were polarized by voltage drops on them that were caused by direct current flow. In this case, the transition voltage of the varactor was enhanced by the voltage drop on the forward-biased diode. Since the transition voltage determines the voltage region in which the varactor protect circuit devices connected in series to the varactor the presented results may help to tune this voltage region.     

PtSi／n—Si肖特基势垒二极管的研制

本文利用ＰｔＳｉ／ｎ－Ｓｉ接触试制成一种新的肖特基势垒二极管，其反向击穿电压一般在１５Ｖ以上，最高达到３５Ｖ。测试了它的Ｉ－Ｖ特性，并与理论计算结果进行了比较和分析。     

一种积累型槽栅超势垒二极管

提出了一种积累型槽栅超势垒二极管,该二极管采用N型积累型MOSFET,通过MOSFET的体效应作用降低二极管势垒。当外加很小的正向电压时,在N+区下方以及栅氧化层和N-区界面处形成电子积累的薄层,形成电子电流,进一步降低二极管正向压降;随着外加电压增大,P+区、N-外延区和N+衬底构成的PIN二极管开启,提供大电流。反向阻断时,MOSFET截止,PN结快速耗尽,利用反偏PN结来承担反向耐压。N型积累型MOSFET沟道长度由N+区和N外延区间的N-区长度决定。仿真结果表明,在相同外延层厚度和浓度下,该结构器件的开启电压约为0.23 V,远低于普通PIN二极管的开启电压,较肖特基二极管的开启电压降低约30%,泄漏电流比肖特基二极管小近50倍。     

nMOSFET低能X射线辐照特性研究

讨论了MOSFET的辐照损伤机理,通过低能（10keV）X射线辐照试验,分析了不同X射线辐照总剂量、不同剂量率对nMOSFET单管的转移特性以及阈值电压的影响。结果表明X射线辐照对nMOSFET的阈值电压变化的影响与^60Co辐照影响的规律基本一致。     

Self-pumped parametric amplification and oscillation of Gunn-effect diodes

This letter describes self-pumped parametric effects resulting from the admittance variations of a domain which occur not when the domain grows near the cathode and is quenched at the anode, but when the bias voltage is varied by an RF output voltage. It is shown that a parametric change in admittance appears in a diode self-pumped by a voltage with a fundamental frequency and that additional admittance appears in a diode self-pumped by a voltage with a harmonic frequency.     

Experimental analysis for the large-amplitude high-efficiency mode of oscillation with Si avalanche diodes

This paper presents the result of an investigation aiming to clarify the large-amplitude oscillation mechanisms of a Si avalanche diode with high efficiency, a part of which was already reported in [6], by varying circuit conditons and the shapes of applied voltage pulses. Applying a pulse resistive, transient voltage across and current through the diode have been observed by varying the rise time of the source voltage. As a result, variations of these waveforms have been revealed with decreasing the rise time and if the slope of the diode voltage at the breakdown is large than 100 V/ns, damping oscillation has been observed with the amplitude increasing proportionally to this slope. This damping oscillation plays a significant role in initiating the stable large-amplitude oscillation. Using a resonant cavity, voltage and current waveforms at various points have been observed and analyzed for various cavity lengths and applied source voltages. The analysis shows that the voltage wave-form across the diode coincides with the superimposed waveforms of the wave incident on and the wave reflected from the diode, the latter being delayed about 60 ps with respect to the former. This oscillation mechanism is considered to be very close to the TRAPATT oscillation. The details of experimental results, oscillation characteristics, and their analyses are explained.     

Computer Simulation of a 5.7GHz, 110kW Transit-Time Oscillator

A high-power transit-time oscillator producing 110kW at 5.7GHz in the TM₀₁₀ cavity mode is described. The device comprises a temperature-limited diode electron gun operating at 40A in the range from 28kV to 35kV and an intermediate coaxial cavity from which the microwave power is extracted through a TEM coaxial guide. The diode serves also as a resonant cavity, where electromagnetic oscillations are grown from noise. The effect of the applied voltage on both the output microwave power and the instability saturation time has been investigated leading to an optimal diode voltage of 33kV.     

A novel dynamic memory cell with internal voltage gain

A 2T1D dynamic memory cell with two transistors (T) and a gated diode (D) is presented. A gated diode is a two terminal MOS device in which charge is stored when a voltage above the threshold voltage is applied between the gate and the source, and negligible charge is stored otherwise. The gated diode acts as a nonlinear capacitance for voltage boosting, where voltage for 1-data is boosted high and voltage for 0-data stays low, achieving significant voltage gain of the internal stored voltage, higher signal margin, higher current drive and low-voltage memory operation. Details about the gated diode structure, its signal amplification, the memory cell circuits and the array structure, some hardware and test results are presented, followed by comparison to other memory cells and future directions.     

Long-wavelength multiple-quantum-well voltage-controlled bistablelaser diodes

We have investigated static and dynamic characteristics of a multiple-quantum-well (MQW) voltage-controlled bistable laser diode at 1.5 μm. Using the quantum confined Stark effect, the absorption coefficient and the absorption band edge of the saturable absorption region are controlled by applied voltage, resulting in easy change of the hysteresis width and the threshold current. Applied voltage from below the current injection regime to the saturable absorption region, typically the reverse bias voltage, allows faster turn-off switching speed due to the carrier sweep-out by the applied electric field, MQW bistable lasers with InGaAs-InP, InGaAs-InGaAsP and InGaAs-InAlAs systems and several kinds of well numbers were fabricated and their threshold current and switching characteristics are compared. A hysteresis width change of about 20 mA was obtained by changing the applied voltage of about 1 V in each case, Less than 100 ps turn-on switching time with injection light of 1-mW peak intensity was obtained. The device can be switched-on by injection light with about 50 nm bandwidth, and the minimum input light switching intensity of less than 10 μW is achieved around the absorption peak wavelength of the saturable absorber. The InGaAs-InAIAs system has the advantage of low voltage bias at the saturable absorber, because the absorption edge is sharper than other materials due to its high conduction band offset. It has a turn-off switching time of less than 100 ps at the applied voltage height of 2.0 V. And also, memory operation with the repetition rate of 2 GHz has been achieved using input light and the applied voltage