氮化镓基高电子迁移率晶体管栅电流输运机制研究

制备了与AlGaN/GaN高电子迁移率晶体管栅极结构与性能等效的圆形肖特基二极管结构,测量了器件的变温电流-电压特性,研究其在正向与反向偏压条件下的载流子输运过程。结果表明:(1)正向低偏压线形区的电流主要为缺陷辅助隧穿电流,而体电阻效应显著的高偏压区,经典热发射机制占主导地位;(2)AlGaN势垒层中的极化电场对器件的反向漏电流起重要作用,载流子的主要输运过程为Frenkel-Poole发射机制。     

垂直纳米线晶体管的制备技术

对目前垂直纳米线晶体管的制备技术进行了综述.首先根据器件结构取向介绍了纳米线晶体管的分类,即水平纳米线晶体管和垂直纳米线晶体管,比较了这两类不同结构晶体管的优缺点,阐述了垂直纳米线晶体管的优势及其潜在应用价值.重点介绍了两种主流的垂直纳米线晶体管的制造方法,即自下而上方法和自上而下方法,自上而下方法则又分为后栅工艺和先栅工艺.随后详细比较了它们之间的不同.最后,对垂直纳米线晶体管制造过程中的工艺挑战进行了分析,提出了几种可行的解决方案,并预测了垂直纳米线晶体管未来的发展趋势,特别是在低功耗器件及3D存储器等方面的发展走向.     

硅基单电子晶体管的制备

硅基单电子晶体管是一种极具潜力的新型量子器件。大多数硅基单电子晶体管的制备方法可以很好地与主流的CMOS工艺兼容。介绍了硅基单电子晶体管一些典型的具体制备工艺和方法以及该领域近年来的研究热点。     

热电子晶体管及其研究进展

热电子晶体管是依靠热电子携带输入信息,并使之在器件中放大的。这种器件具有工作速度高,使用一个元件就可以完成某种复杂的逻辑功能等优点。本文首先介绍热电子晶体管的基本原理,然后介绍几种重要的热电子晶体管,包括隧道热电子输运放大(THETA)器件,共振隧道热电子晶体管(RHET)和电荷注入晶体管(CHINT)等。     

GaAs基改性高电子迁移率晶体管(MHEMT)的计算机模拟与优化

讨论了针对GaAs基改性高电子迁移率晶体管(MHEMT)的异质层结构参数的设计优化方法,详细给出了有关的设计步骤与公式。在数值分析与比较的基础上,并综合考虑材料生长与器件工艺的简便性,得到一组优化的MHEMT异质层结构设计参数。模拟所得的器件DC与RF特性充分显示其在功率与低噪声应用上的巨大潜力。验证性的1μm×200μmMHEMT取得的fT=30GHz、fmax=170GHz的结果佐证了理论分析的正确性。     

Vertical Organic Field‐Effect Transistors

Field‐effect transistors are the fundamental building blocks for electronic circuits and processors. Compared with inorganic transistors, organic field‐effect transistors (OFETs), featuring low cost, low weight, and easy fabrication, are attractive for large‐area flexible electronic devices. At present, OFETs with planar structures are widely investigated device structures in organic electronics and optoelectronics; however, they face enormous challenges in realizing large current density, fast operation speed, and outstanding mechanical flexibility for advancing their potential commercialized applications. In this context, vertical organic field‐effect transistors (VOFETs), composed of vertically stacked source/drain electrodes, could provide an effective approach for solving these questions due to their inherent small channel length and unique working principles. Since the first report of VOFETs in 2004, impressive progress has been witnessed in this field with the improvement of device performance. The aim of this review is to give a systematical summary of VOFETs with a special focus on device structure optimization for improved performance and potential applications demonstrated by VOFETs. An overview of the development of VOFETs along with current challenges and perspectives is also discussed. It is hoped that this review is timely and valuable for the next step in the rapid development of VOFETs and their related research fields.     

基于垂直结构的有机薄膜晶体管

介绍了基于垂直结构的有机薄膜晶体管的器件结构、工作原理以及相关的研究进展。通过对垂直结构的有机薄膜晶体管的特性分析,探讨了采用这种结构的有机薄膜晶体管驱动有机发光二极管的可行性。此项研究为发展新型全有机的柔性显示器提供了新的思路。     

On the Pseudomorphic High Electron Mobility Transistors (PHEMTs) With a Low-Temperature Gate Approach

The characteristics of AlGaAs/InGaAs/GaAs depletion-mode (D-mode) and enhancement-mode (E-mode) pseudomorphic high electron mobility transistors (PHEMTs) fabricated using an electroless-plated (EP) deposition approach are investigated. Under the low-temperature and low-energy conditions, the EP deposition approach can form a better metal–semiconductor interface. For the studied devices, with a $hbox{1} times hbox{100} muhbox{m}^{2}$ gate dimension, excellent characteristics of the maximum drain saturation current (168.9 mA/mm) and extrinsic transconductance (225.8 mS/mm) are obtained for the D-mode device. The corresponding values for the E-mode device are 152.5 mA/mm and 211.7 mS/mm, respectively. Moreover, the EP approach also has the advantages of easy operation and low cost.      

垂直发射极镇流电阻在HBT中的发射极电流集边效应中的作用

在异质结双极晶体管(HBT)功率器件中可以引入外延生长的发射极镇流电阻,以改善其热稳定性.通过理论计算和实验表明这种低掺杂的外延层不仅能作为镇流电阻,而且在功率HBT器件中还能非常有效地降低发射极电流集边效应.     

高电子迁移率晶体管器件模型

（Ａｌ．Ｇａ）Ａｓ－ＧａＡｓ高电子迁移率晶体管（ＨＥＭＴ）具有跨导大、截止频率高、噪声低、开关速度快以及功耗低等特点。是一种比ＭＥＳＦＥＴ优越的新型器件。在器件模拟这一领域，已经发展了一维分析模型、二维数值模型或半数值模型以及针对小尺寸器件的Ｍｏｎｔｅ Ｃａｒｌｏ模型。对部分一维和二维器件模型作了综合介绍和分析。     

垂直发射极镇流电阻在HBT中的发射极电流集边效应中的作用

在异质结双极晶体管(HBT)功率器件中可以引入外延生长的发射极镇流电阻,以改善其热稳定性.通过理论计算和实验表明这种低掺杂的外延层不仅能作为镇流电阻,而且在功率HBT器件中还能非常有效地降低发射极电流集边效应.     

Analysis and Simulation of Vertical Complementary Silicon Bipolar Transistors

The features of modern complementary bipolar technologies (CB-technologies) for analog applications have been analyzed and the main trends in their development are considered. Different industrial CBtechnologies are compared on the basis of two parameters of complementarity, namely the quality factor (βV _A ) and Johnson’s parameter (BV _CEO f _T ). The p-epitaxial-planar CB-technology has been studied by the method of two-dimensional numerical simulation using the TCAD Sentaurus software for vertical n–p–n and p–n–p transistors. A careful calibration of the parameters of technological and electrophysical 2D models on the basis of test structures has shown sufficient accuracy of the used methodology for practice.     

高性能纵向pnp晶体管的研制

pnp晶体管中由于空穴的迁移率较电子的迁移率低得多,再加上纵向pnp管有比npn管严重得多的基区宽度调变效应,一般情况下,难以使纵向pnp管的性能与npn管的性能相媲美。我们从理论上分析了提高纵向pnp管性能的途径,并设计了一套新的工艺流程。在p型外延材料上研制出了BV_(ceo)≥90V、V_(be)≤0.8V、f_T=900MHz、V_(ces)=0.2V、β=60～150、厄利电压大于150V的纵向pnp晶体管。在P型单晶材料上研制出了BV_(ceo)≥65V、f_T≥560MHz、β=60～150的纵向pnp晶体管。具有这种性能的纵向pnp管目前在国内外还很少见。     

Hybrid Molecular/Inorganic Semiconductor Transistors in Vertical Architectures

Inorganic semiconductor–metal–semiconductor transistors were developed more than 40 years ago. However, despite being potentially attractive for fast switching and sensor applications, they are difficult to produce and usually show low base transport factors, thereby limiting their applicability. Recent developments in hybrid organic/inorganic semiconductor–metal–semiconductor transistors, however, demonstrate that high‐gain transistors can be produced using simple technologies. Additionally, their fabrication is compatible with well‐established silicon electronics technology, which provides an enormous advantage. These devices, built in a vertical architecture, offer attractive new possibilities due to the large variety of available molecular semiconductors, opening the possibility of incorporating new functionalities in silicon‐based devices.     

Vertical InAs Nanowire Wrap Gate Transistors on Si Substrates

We report on InAs enhancement-mode field-effect transistors integrated directly on Si substrates. The transistors consist of vertical InAs nanowires, grown on Si substrates without the use of metal seed particles, and they are processed with a 50-nm-long metal wrap gate and high-$kappa$ gate dielectric. Device characteristics showing enhancement-mode operation are reported. The output characteristics are asymmetric due to the band alignment and band bending at the InAs/Si interface. The implemented transistor geometry can therefore also serve as a test structure for investigating the InAs/Si heterointerface. From temperature-dependent measurements, we deduce an activation energy of about 200 meV for the InAs/Si conduction band offset.      

一种基于单电子晶体管的二阶低通滤波器

在研完单电子晶体管(SET)I-V特性的基础上，阐明了一种分区处理法，设计了一个SET积分器电路。并据此实现了一个SET二阶低通滤波器，说明了该滤波器的工作条件、结构、性能、参数和特点。仿真结果表明，该滤波器的传输特性与采用其它两种方法描述SET I-V特性所构成的滤波器的传输特性有良好的一致性。文中所提出的SET I-V特性分区处理法，同样适用于SET在其它功能电路中的应用。     

Anomalous Kink Effect in GaN High Electron Mobility Transistors

An anomalous kink effect has been observed in the room-temperature drain current $I_{D}$ versus drain voltage $V_{rm DS}$ characteristics of GaN high electron mobility transistors. The kink is originated by a buildup (at low $V_{rm DS}$) and subsequent release (at high $V_{rm DS}$) of negative charge, resulting in a shift of pinch-off voltage $V_{P}$ toward more negative voltages and in a sudden increase in $I_{D}$. The kink is characterized by extremely long negative charge buildup times and by a nonmonotonic behavior as a function of photon energy under illumination. The presence of traps in the GaN buffer may explain both spectrally resolved photostimulation data and the slow negative charge buildup.      

Contact Doping for Vertical Organic Field‐Effect Transistors

Doping is a powerful tool to overcome contact limitations in short‐channel organic field‐effect transistors (OFETs) and has been successfully used in the past to improve the charge carrier injection in OFETs. The present study applies this familiar concept to the architecture of vertical organic field‐effect transistors (VOFETs), which are often severely limited by injection due to their very short channel lengths. The present study shows that the performance of p‐type VOFETs with pentacene as an active material can be significantly enhanced by the addition of the common p‐dopant C₆₀F₃₆ as a thin injection layer underneath the VOFET source electrode, resulting in an increase of On‐state current and On/Off ratio by one order of magnitude. The present study further investigates mixed injection layers of pentacene and the p‐dopant and finds that the improvement is less pronounced than for the pure dopant layers and depends on the concentration of dopant molecules in the injection layer. Through application of the transfer length method to equivalent OFET geometries, the present study is finally able to link the observed improvement to a decrease in transfer length and can thus conclude that this length is a crucial parameter onto which further improvement efforts have to be concentrated to realize true short‐channel VOFETs.     

基于复合管改进型电流镜的CCCⅡ电路

提出了一种新型的电流控制第二代电流传输器电路。该电路由6个复合管改进型电流镜和1个跨导线性环组成,该电路的电流传输精度远高于基于基本电流镜和级联电流镜实现的电流控制第二代电流传输器(CCCII)的电流传输精度。对电路原理进行了分析,并进行了硬件实验,实验结果表明频率在0～1.3MHz范围内能很好地满足CCCII的电流和电压特性关系,从而证明提出的电路是正确的。