硅基隧穿二极管

隧穿二极管是一种很有前途的基于带隙工程的异质结构量子器件,其电流电压(I-V)曲线中所呈现的微分负阻特性能够用于开发多种不同的电路功能。在最近的研究中,空穴型双势垒单势阱共振隧穿二极管得到了实现,为Si1-xGex/Si异质结隧穿二极管器件的改进和电路应用打下了良好的基础。     

小偏压下阱中阱结构的量子隧穿特性及其实现

共振隧穿是电子的隧穿概率在某一个能量值附近以尖锐的峰值形式出现的隧穿,是目前为止最有希望应用到实际电路和系统的量子器件之一,其特点是器件的响应速度非常快。本文用传递矩阵的方法分别计算了在外加偏压下,对称双势垒、三势垒应变量子阱结构的透射系数与入射电子能量和隧穿电流与偏置电压的关系,模拟了应变多量子阱结构的隧穿系数和I-V特性曲线。计算得到隧穿电流峰值位置与实验测试值符合得很好,对于设计共振隧穿二极管并为进一步实验提供理论指导具有重要的意义。     

室温下nc-Si/SiO2多层膜结构中的共振隧穿现象

采用等离子体淀积和原位氧化技术,并结合后续的热退火处理制备了nc-Si/SiO2 多层膜结构。通过电流电压特性对室温下器件中的载流子输运过程进行了表征。在正向和反向偏压下的电流电压特性曲线中都表现出了由于共振隧穿引起的负微分电导。共振隧穿产生的峰值电流对应的电压值与器件结构中的势垒层厚度相关,势垒层越厚,发生隧穿的峰值电压越高。文中通过器件的能带结构简图和等效电路图对正向、反向偏压下的共振隧穿峰值电压差异进行了细致的分析。     

GeSi/Si共振隧穿二极管

GeSi/Si共振隧穿二极管主要包括空穴型GeSi/SiRTD、应力型GeSi/SiRTD和GeSi/Si带间共振隧穿二极管三种结构。着重讨论了后两种GeSi/Si基RTD结构;指出GeSi/Si异质结的能带偏差主要发生在二者价带之间(即ΔEv>ΔEc),形成的电子势阱很浅,因此适用于空穴型RTD的研制;n型带内RTD只有通过应力Si或应力GeSi来实现,这种应力型RTD为带内RTD的主要结构;而带间GeSi/SiRITD则将成为更有应用前景的、性能较好的GeSi/SiRTD器件结构。     

共振隧穿二极管(RTD)的物理模型——共振隧穿器件讲座(3)

介绍了共振隧穿二极管物理模型的量子力学基础,重点讲解共振隧穿两种物理模型,从不同维度隧穿的特点分析共振隧穿和非共振隧穿的区别,为以后讨论分析共振隧穿器件的特性奠定基础。     

共振隧穿器件及其集成技术发展趋势和最新进展

介绍了共振隧穿器件及其特点,论述了该类器件及其集成技术的发展趋势和最新进展,特别是SiO 2S/iS/iO 2共振隧穿二极管及其集成电路的研制成功是一个突破性的进展。     

利用共振隧穿器件制作太赫兹波源

太赫兹波是振荡频率在100GHz～10THz范围的电磁波,利用共振隧穿器件高频高速的特点,适宜制作此波段的振荡源器件。指出与其他类型的太赫兹源器件相比,共振隧穿型太赫兹波源器件具有体积小、重量轻、便于与控制电路集成以及易于进行调制等特点;此外,还适宜用Si透镜进行功率合成,增大其总发射功率。给出几种重要太赫兹共振隧穿器件的结构、制造工艺和器件性能,作为太赫兹技术领域的研究人员选择太赫兹波源器件的参考。     

新型电子器件和光学器件的共振隧穿结构

描述了一种新型共振隧穿结构器件，这种器件包含了通过可变间隙超晶格能量滤波器（ＶＳＳＥＦ）中的耦合量子附态的隧穿过程．论证了通过ＡｌＡｓ／ＧａＡｓＶＳＳＥＦ器件高能态和ＡｌＧａＡｓ／ＧａＡｓ超晶格受激态的共振隧穿，描述了这种器件作为较高功率微波源和共振隧穿晶体管的应用，并讨论了共振隧穿结构作为雪崩探测器和红外发射器等光学器件的潜在应用．     

共振隧穿二极管型光探测器和光调制器

将共振隧穿二极管(RTD)的核心结构——双势垒系统与光探测器和调制器的原理相结合可构成共振隧穿光探测器和共振隧穿光调制器。这些器件既保持了RTD高频、高速的特点,同时又具备了光探测器和光调制器原有的功能,可用于光电集成电路。介绍了这种具有代表性的RTD型光电器件的工作原理、器件结构、制造工艺、器件参数测试等,为此类器件在国内的设计和研制奠定基础。     

轴向应变对双势垒结构共振隧穿的影响

首先介绍了共振隧穿理论和一种新效应--介观压阻效应,对AlxGa1-xAs/GaAl/AlxGa1-xAs共振隧穿双势垒结构的轴向施加压应变作了分析,然后计算了轴向应变对垒宽和垒高的影响,对透射系数和隧穿电流用Matlab作了仿真.发现压应变可以使隧穿电流线性增加,偏压不同电流增加的速率也不同,为设计共振隧穿器件提供了理论依据.     

Sidewall spacer defined resonant interband tunneling diodes

We report on a contacting and fabrication scheme for a sub-500 nm InAs/AlSb/GaSb resonant interband tunneling diode (RITD) without using any fine-line lithography. Epitaxial regrowth on patterned substrates combined with sidewall spacer technology is used to define the device dimensions. During regrowth, the crystal facet termination obtained by choosing the appropriate orientation for the device is utilized to make electrical contact to the device in the desired directions and to isolate the device in all other directions. The concept, fabrication process, current-voltage characteristics of the device, and a comparison with RITDs fabricated in a conventional manner are reported.     

Tri-state logic using vertically integrated Si-SiGe resonant interband tunneling diodes with double NDR

A vertically integrated npnp Si-based resonant interband tunneling diode (RITD) pair is realized with low-temperature molecular beam epitaxy by stacking two RITDs with a connecting backward diode between them. The current-voltage characteristics of the vertically integrated RITD pair demonstrates two sequential negative differential resistance regions in the forward-biasing condition. Tri-state logic is demonstrated by using the vertically integrated RITDs as the drive and an off-chip resistor as the load.     

Si/SiGe Resonant Interband Tunneling Diodes Incorporating $delta$-Doping Layers Grown by Chemical Vapor Deposition

This is the first report of a Si/SiGe resonant interband tunneling diodes (RITDs) on silicon substrates grown by the chemical vapor deposition process. The nominal RITD structure forms two quantum wells created by sharp $delta$-doping planes which provide for a resonant tunneling condition through the intrinsic spacer. The vapor phase doping technique was used to achieve abrupt degenerate doping profiles at higher substrate temperatures than previous reports using low-temperature molecular beam epitaxy, and postgrowth annealing experiments are suggestive that fewer point defects are incorporated, as a result. The as-grown RITD samples without postgrowth thermal annealing show negative differential resistance with a recorded peak-to-valley current ratio up to 1.85 with a corresponding peak current density of 0.1 $hbox{kA/cm}^{2}$ at room temperature.      

谐振带间隧道二极管

谐振带间隧道二极管是一种双势垒量子阱极性器件,其突出特点在于其峰－谷电流 极管（属双势垒量子阱非极性器件）高。对其基本工作原理及结构进行了分析,介绍了并讨论了这种结构在电路中的两项应用。     

Improved vertically stacked Si/SiGe resonant interband tunnel diode pair with small peak voltage shift and unequal peak currents

A vertically integrated and serially connected npnp Si-based resonant interband tunnelling diode (RITD) pair is realised with low temperature molecular beam epitaxy (MBE) by monolithically stacking two RITDs with different spacer thicknesses. The asymmetric design manifests as unequal peak current densities that provide for much larger and uniform separation of the holding states for multi-valued logic. A /spl delta/-doped backwards diode connects the two serially connected RITDs with a very small series resistance. The I-V characteristic of the improved vertically integrated RITDs demonstrates two negative differential resistance (NDR) regions in the forward biasing condition with a small peak shift and unequal peak currents.     

A vertical resonant tunneling transistor for application in digitallogic circuits

A vertical resonant tunneling transistor (VRTT) has been developed, its properties and its application in digital logic circuits based on the monostable-bistable transition logic element (MOBILE) principle are described. The device consists of a small mesa resonant tunneling diode (RTD) in the GaAs/AlAs material system surrounded by a Schottky gate. We obtain low peak voltages using InGaAs in the quantum well and the devices show an excellent peak current control by means of an applied gate voltage. A self latching inverter circuit has been fabricated using two VRTTs and the switching functionality was demonstrated at low frequencies     

Experimental investigation of the temperature dependence of InAs-AlSb-GaSb Resonant Interband tunnel diodes

The temperature dependence of the current-voltage (I-V) characteristics of InAs-AlSb-GaSb resonant interband tunnel diodes (RITDs) has been investigated from 223 to 423 K. Several device structures were examined, with tunnel barrier thicknesses from 0.6 to 2.0 nm. For all barrier thicknesses, the peak current density (J/sub p/) decreases slightly as the temperature is increased, while the valley current density (J/sub v/) increases with temperature. We found that the temperature rate of change for the peak current density with temperature (/spl part/J/sub p///spl part/T) is nearly independent of barrier thickness, while J/sub v/ increases more rapidly for devices with thicker barriers. In addition, the peak voltage (V/sub p/) was found to be independent of temperature, regardless of barrier thickness. However, the valley voltage (V/sub v/) was observed to decrease with increasing temperature, with more rapid changes observed for RITDs with thicker barriers. Comparison of the temperature performance of RITDs with different barrier thicknesses shows that devices with thinner barriers have I-V characteristics that are less sensitive to temperature, as well as having larger peak and valley current density and voltage for the temperature range from 223 to 423 K. To our knowledge, this is the first report of the temperature dependence of the device characteristics of Sb-based RITDs as a function of barrier width.     

12 GHz clocked operation of ultralow power interband resonanttunneling diode pipelined logic gates

We report on the successful demonstration of a functionally complete set of logic gates based on resonant interband tunneling diodes (RITDs) with a maximum operating frequency in excess of 12 GHz. At this high frequency of operation, the power dissipation is remarkably low-on the order of 0.5 mW per gate. The circuits for all gates, AND, OR, XOR, and INV, shared the same layout geometry, consisting of two Schottky diodes and three RITDs. Logical functionality was determined solely by varying the relative areas of the devices     

Digital integrated circuit using integrated InAlAs/InGaAs/InP HEMTsand InAs/AlSb/GaSb RITDs

The demonstration of the first integrated circuit using monolithically integrated InAs/AlSb/GaSb resonant interband tunnelling diodes (RITDs) and InAlAs/InGaAs/InP high electron mobility transistors (HEMTs) is reported. A D-flip-flop (D-FF) was implemented using the monostable/bistable logic element (MOBILE) circuit architecture, with a measured effective voltage gain in excess of 380. Power dissipation of less than 2.8 mW/gate was measured