光电双基区晶体管中的光控电流开关效应

光电双基区晶体管体在光电混合模式工作条件下具有光控“Ｓ”型负阻特及其光控电流开关效应。测量了光照时ＩＢＥ－ＶＢＥ特性,Ｉｔｈ－Ｒｃ特性等曲线。并利用用电注入双基区晶体管的“Ｓ”型负阻产生机理解释了测得的结果。     

基于阳极弱反型层消除负阻效应的新型SOI LIGBT

在SOI衬底上,制作了一种基于阳极弱反型层消除负阻效应的新型横向绝缘栅双极晶体管(SOI AWIL-LIGBT)。利用反型所形成的高阻值电阻来使PN结阳极快速导通,阳极P+区中的空穴可以更快地注入漂移区,从而消除负阻效应。仿真结果表明,该新型LTGBT在保证关断速度不变的情况下,击穿电压为307 V(漂移区长度为18 μm)比,比常规SA-LIGBT提升了56%,并消除了负阻效应。     

一种新型结构的InGaP/GaAs负阻异质结晶体管

利用硅双基区晶体管（DUBAT）产生负阻的原理,针对HBT器件结构和MBE材料结构的特点,设计并研制出一种基区刻断结构的负阻型HBT (NDRHBT) . 经过特性和参数测试,证明此种NDRHBT具有显著的微分负阻效应,并发现负电流区负阻效应和光照可改变其I-V特性,器件模拟结果和测试结果基本一致.     

一种新型结构的InGaP/GaAs负阻异质结晶体管

利用硅双基区晶体管(DUBAT)产生负阻的原理,针对HBT器件结构和MBE材料结构的特点,设计并研制出一种基区刻断结构的负阻型HBT(NDRHBT).经过特性和参数测试,证明此种NDRHBT具有显著的微分负阻效应,并发现负电流区负阻效应和光照可改变其I-V特性,器件模拟结果和测试结果基本一致.     

光电双向负阻晶体管的数值模拟与实验研究

光电双向负阻晶体管(PBNRT)是一种新型S型光电负阻器件.本文对它的光电负阻特性进行了数值模拟和实验研究,给出了器件等效电路.PBNRT在光电混合工作模式下具有光控电流开关效应,可通过光照和控制电压两种控制方式改变器件的S型负阻特性.模拟和实验结果均表明:光照强度增大,维持电压基本保持不变,转折电压减小,负阻电压摆幅减小;而增大控制电压,维持电压和转折电压均增大,输出负阻特性曲线右移.上述特点使得PBNRT可望在光电开关、光控振荡和光电探测等方面有很好的应用前景.     

新型恒压控制型负阻HBT的研制进展

研究了HBT产生负阻的可能机制,通过对材料结构和器件结构的特殊设计,采用常规台面HBT工艺,先后研制出3类高电流峰谷比的恒压控制型负阻HBT.超薄基区HBT的负阻特性是由超薄基区串联电阻压降调制效应造成的,在GaAs基InGaP/GaAs和AlGaAs/GaAs体系DHBT中均得到了验证.双基区和电阻栅型负阻HBT均为复合型负阻器件.双基区负阻HBT通过刻断基区,电阻栅负阻HBT通过在集电区制作基极金属形成集电区反型层,构成纵向npn与横向pnp的复合结构,由反馈结构(pnp)的集电极电流来控制主结构(npn)的基极电流从而产生负阻特性.3类负阻HBT与常规HBT在结构和工艺上兼容,兼具HBT的高速高频特性和负阻器件的双稳、自锁、节省器件的优点.     

发射极电流集边效应理论的SPICE模拟验证

发射极电流集边效应是由晶体管基极电阻的自偏压引起的 ,描述该效应的微分方程早已建立 ,这里设计了一种用 SPICE验证精确解 /近似解的新方法 .结果表明 :近似解是在 V( x) VT 的前提条件下求得的 ,仅在弱注入区和中等注入区适用 ,不能给出在强注入区和极强注入区的归一化电位和电流密度的分布函数 ;相反 ,基于精确解的理论却能给出从弱注入区到极强注入区的归一化电位和电流密度的分布函数 ,且与用 SPICE模拟得到的结果吻合 .结论是 :从整体来看 ,精确解的理论比近似解的理论描述该效应要稍好一些 ,因为前者的适用范围比后者宽 .应当强调指出 ,该效应     

发射极电流集边效应理论的SPICE模拟验证

发射极电流集边效应是由晶体管基极电阻的自偏压引起的,描述该效应的微分方程早已建立,这里设计了一种用SPICE验证精确解/近似解的新方法.结果表明:近似解是在V(x)(《)VT的前提条件下求得的,仅在弱注入区和中等注入区适用,不能给出在强注入区和极强注入区的归一化电位和电流密度的分布函数;相反,基于精确解的理论却能给出从弱注入区到极强注入区的归一化电位和电流密度的分布函数,且与用SPICE模拟得到的结果吻合.结论是:从整体来看,精确解的理论比近似解的理论描述该效应要稍好一些,因为前者的适用范围比后者宽.应当强调指出,该效应正是发生在强注入区和极强注入区.     

VVMOS功率晶体管的负阻击穿

VVMOS晶体管是一种开有V形槽的垂直沟道高频功率MOS场效应器件,它的一个主要优点是与其它MOS器件一样不会发生二次击穿,然而近来一些作者报道MOS器件有负阻击穿效应,而这种负阻击穿效应也会引起二次击穿,导致器件烧毁。我们在测量自制的VVMOS晶体管时,也观察到了负阻击穿,经过研究,提出了纵向寄生npn双极晶体管的VVMOS晶体管负阻击穿模型,在此基础上还提出了几种抑制负阻击穿效应的方法,在采用了这些方法后,负阻击穿效应被减弱,甚至被消除,从而证实了所提出的VVMOS晶体管负阻击穿模型。     

低温、小电流、高增益硅双极晶体管的研究与设计

介绍了一种用于低温、小注入电流条件下工作的新型多晶硅发射区双极晶体管,并给出了晶体管电流增益的低温模型。该模型考虑了低温下多子和少子的冻析效应、禁带变窄效应、Auger复合、多晶硅发射效率增强效应等。在此基础上,通过用SUPREM-Ⅲ和PISCES-Ⅱ进行了工艺模拟和器件模拟,最后完成了实际版图制作和工艺流水。对管子的测试表明,该晶体管具有极好的小电流特性,在0.5μA的注入电流下其共射电流放大倍数可高达1000,在低温(77K)下其β仍可达70左右,能够正常工作。     

Characteristics of static induction transistors: Effects of series resistance

It is established experimentally that the I-V characteristics of a static induction transistor (SIT) and their temperature dependence are consistent with a major current transport mechanism of majority-carrier injection control plus the effect of series channel resistance. The I-V characteristics follow an exponential behavior in the low-current region and change to approximately a linear-or square-law relation in the high-current region where the negative feedback effect of the series channel resistance becomes pronounced. That the series channel resistance is small in the SIT and satisfies the condition that the product of series channel resistance and dc intrinsic transconductanee is less than unity is experimentally verified. The voltage amplification factor in the SIT has been confirmed to be almost constant for wide variations of drain current and ambient temperature.     

Analysis of negative differential resistance in theI-V characteristics of shorted-anode LIGBT's

The physical mechanism responsible for the negative differential resistance (NDR) in the current-voltage characteristics of the shorted anode lateral insulated gate bipolar transistor (SA-LIGBT) is explained through two-dimensional numerical simulation. The NDR regime is an inherent feature of all SA-LIGBTs, and results from the two different conduction mechanisms responsible for current flow in the device. These conduction mechanisms are minority-carrier injection and majority-carrier flow. Since both the anode geometry and the doping profile control the onset and the degree of minority-carrier injection, the effect these parameters have on the NDR is investigated. A simple lumped-element equivalent model of the SA-LIGBT allows qualitative predictions to be made on how changes in the device geometry and doping profiles influence the NDR regime. It is shown that conductivity modulation is a necessary but not sufficient condition for the occurrence of negative resistance in SA-LIGBT devices. Also required is a large voltage drop in the high-resistivity drift region before conductivity modulation is initiated. This causes small changes in the anode current level, greatly decreasing the total resistance across the drift region     

Parasitic MOSFET degradation induced by Fowler-Nordheim injection

Degradation induced by Fowler-Nordheim (F-N) electron injection is observed in a parasitic MOS transistor associated with a MOS transistor's edge region. A bump appears in the subthreshold region of both an n-channel transistor after positive gate biased F-N injection and a p-channel transistor after negative gate biased F-N injection. It is found that the effective gate-oxide thickness of a parasitic transistor is 30 nm. As thinner gate oxide is used, the amount of the charge injected into the gate oxide may increase due to increased electric fields     

一种新型硅三端负阻器件

提出并研制成一种新型硅三端负阻器件。该器件由一n沟耗尽型MOS管、一横向pnp双极晶体管和一个电阻集成而得。它具有“双负阻”特性和正阻区阻值易于控制等特点。由理论计算出的器件I_c—V_(CB)特性和负阻参数与实验结果符合良好。     

Thermal effects on the characteristics of AlGaAs/GaAsheterojunction bipolar transistors using two-dimensional numericalsimulation

Two-dimensional numerical simulations incorporating the spatial distributions of the energy band and temperature were used to study AlGaAs/GaAs heterojunction bipolar transistor characteristics. It was found that the negative differential resistance and the reduction of the base-emitter voltage for a constant base current in the active region are due to thermal effects. The differential current gain and cutoff frequency decrease when the transistor is operated at high power levels. The temperature distribution of the transistor operated in the active region shows a maximum at the collector region right beneath the emitter mesa. When the transistor is operated in the saturation region, the emitter contact region may be at a slightly lower temperature than the heat sink temperature. This thermoelectric cooling effect results from the utilization of the thermodynamically compatible current and energy flow formulations in which the energy band discontinuities are part of the thermoelectric power     

双极晶体管基极电阻的电流特性

本文针对基极电阻随电流变化的实验事实,根据基区电导调制效应,提出了工作在大电流密度水平时,基极电阻R_B(I_B)的理论模型;根据复合效应分析了小电流段R_B(I_B)的变化关系.实验结果与理论模型一致.     

Tunneling injection into modulation doping structures: a mechanismfor negative differential resistance three-terminal high-speed devices

A tunneling injection mechanism into the channel of a modulation doping field effect transistor is discussed. In the presaturation regime of the drain current, the source current exhibits negative differential resistance as a result of the charge control by the gate field in the channel. The tunneling three-terminal device promises high-frequency operation     

精密高速模拟电压开关电路的设计

设计了一种新型模拟电压可切换无触点开关电路。该电路由集成运算放大器和场效应管组成,能有效地消除场效应管的导通电阻和夹断漏电流造成的不利影响,保证开关的精度、稳定度和高速度,并具有可调节的信号放大能力,功能比较接近理想开关。具体分析了开关电路消除导通电阻、减小关断漏电流、提高开关速度的原理。该开关已在实际应用中获得了满意的效果。