GaAs／AlAs异质谷间转移电子器件微波振荡特性的研究

本文介绍了应用直接带隙ＧａＡｓ和间接带隙ＡｌＡｓ构成的量子阱产生异质谷间转移电子效应来制作新毫米波振荡器件一异质谷间转移电子器件，概述了器件的结构和基本的微波工作特性。器件已在８ｍｍ波段输出３２０ｍＷ连续波功率，最高振荡效率８％，脉冲工作时输出功率达２Ｗ，效率１０％，然后着重介绍该器件的振荡频率，输出功率随偏压的变化关系，突出它与常规耿氏器件之间的差异。最后简要描述器件计算机模拟中求出的器件内的电场结构和两能谷电流分布以及正反向偏压下器件交流工作中的电场结构，由此解释了实验中观察到的种种工作特性。从而深化了对异质谷间转移电子器件及其工作机理的研究。     

异质谷间转移电子器件的Monte Carlo模拟研究

使用量子阱能带混合隧穿共振理论和ＭｏｎｔｅＣａｒｌｏ模拟计算研究了异质谷间转移电子器件中的双能谷电子注入、两种谷间转移电子的相互作用、有源层电场分布及异质结电压的触发功能．首次发现了ＧａＡｓ器件中的三能谷谷间电子转移．算得的二极管伏安特性和实验测量结果相吻合．用所得的电场结构图和三能谷电子分布图证明强场畴能直接在阴极端触发，消除了耿氏有源层中的死区．由此说明了器件振荡频率下降和振荡效率升高的特性．     

GaAs／AlAs超晶格Γ－X级联隧穿导致的电场畴

我们研究了掺杂耦合ＧａＡｓ／ＡｌＡｓ超晶格的级联隧穿，在这种结构中，ＡｌＡｓ层Ｘ能谷中的基态能级位于ＧａＡｓ层中Γ能谷的基态（Ｅ（Γ１）；）和第一激发态（Ｅ（Γ２））能级之间．实验结果证明，这种超晶格中的高电场畴是由Γ－Ｘ级联共振隧穿所形成的，而不是通常的相邻量子阱子带的级联共振隧穿所形成的．在这种高场畴中，电子从ＧａＡｓ量子阱的基态隧穿到邻近的ＡｌＡｓ层的Ｘ能谷的基态，然后通过实空间电子转移从ＡｌＡｓ层的Ｘ能谷弛豫到下一个ＧａＡｓ量子阱的Γ能谷的基态．     

新颖的微波器件材料—InGaAs／GaAs异质结构

新颖的微波器件材料──ＩｎＧａＡｓ／ＧａＡｓ异质结构彭正夫，张允，龚朝阳，高翔，孙娟，吴鹏（南京电子器件研究所２１００１６）一、引言众所周知，ＧａＡｓＭＥＳＦＥＴ器件的微波特性主要由沟道中的电子饱和速度和栅长决定．由于ＩｎＧａＡｓ的电子饱和速度比Ｇａ...     

GaAs／A1As异质谷间转移电子器件微波振荡特性的研究

本文介绍了应用直接带隙ＧａＡｓ和间接带隙ＡｌＡｓ构成的量子阱产生异质谷间转移电子效应来制作新毫米波振荡器件－异质谷间转移电子器件。概述了器件的结构和基本的微波工作特性，器件已在８ｍｍ波段输出３２０ｍＷ连续波功率，最高振荡效率８％，脉冲工作时输出功率达２Ｗ，效率１０％，然后着重介绍该器件的振荡频率，输出功率随偏压的变化关系，突出它与常规耿氏器件之间的差异，最后简要描述器件计算机模拟中求出的器件内的电     

GaAs／AlAs超晶格Г—X级联隧穿导致的电场畴

我们研究了掺杂耦合ＧａＡｓ／ＡｌＡｓ超晶格的级联隧穿，在这种结构中，ＡｌＡｓ层Ｘ能谷中的基态能级位于ＧａＡｓ层中Г能谷的基态（ＥГ１）和第一激发态（ＥГ２）能级之间，实验结果证明，这种超晶格中的高电场畴是由Г－Ｘ级联共振隧穿所形成的，而不是通常的相邻量子阱子带的级联共振隧穿所形成的，在这种高场畴中，电子从ＧａＡｓ量子阱的基态隧穿到邻近的ＡｌＡｓ层的Ｘ能谷的基态，然后通过实空间电子转移从ＡｌＡｓ层的     

毫米波高电子迁移率晶体管的二维数值模拟

建立了高电子迁移晶体管（ＨＥＭＴ）的二维数值模型，并用二维数值模拟的方法讨论了ＡｌＧａＡｓ／ＧａＡｓＨＥＭＴ中的ＧａＡｓ沟道层量子阱中二维电子气的物理性质．通过自洽求解薛定谔方程和泊松方程获得了沟道中的电子浓度和横向电场．模拟结果表明栅电压的改变对ＨＥＭＴ器件跨导产生很大的影响．     

GaAs功率MESFET热阻测试与分析

通过对ＧａＡｓ功率ＭＥＳＦＥＴ的热阻分析、测试及相关热试验，促进芯片结构的优化设计和工艺控制，能有效地提高ＧａＡｓ器件的可靠性，以延长通讯卫星及微波电子整机的使用寿命。     

低阈值基横模脊形波导GaAs／AlGaAs单量子阱激光器

本文报道了脊形波导结构ＧａＡｓ／ＡｌＧａＡｓ量子阱激光器的研究成果．我们采用湿法化学腐蚀方法，通过对器件结构参数的优化，制备了性能优越的脊形波导ＧａＡｓ／ＡｌＧａＡｓ量子阱激光器，器件的阈值电流低于１０ｍＡ，最低值为７．３ｍＡ，而且实现了基横模工作，这是国内报道的该结构激光器的最好水平．     

异质结电荷注入晶体管

通过对ＧａＡｓ／ＡｌＧａＡｓ异质结电荷注入晶体管结构和工艺的探索研究，以及对器件工作特性的测量分析，在理论上给出了器件过程的物理机制，并对器件结果提出了进一步的改进措施．     

GaAs/AlAs异质谷间转移电子器件动态工作模式的模拟研究

使用量子阱能带混合隧穿共振理论及MonteCarlo模拟方法计算了GaAs／AlAs异质谷间转移电子器件的静态和动态工作特性．发现有源层中的电场及Г、X和L三能谷的电子布居基本上可分为强场立能谷区和弱场耿氏区两部分．控制掺杂接日的浓度能调制这两区域的相对大小，控制两种谷间转移电子效应的相互作用，从而改变器件的静态和动态性能动态模拟给出了器件的新射频工作模式：上能谷电子区的宽度调制和低场耿氏区电场的上下浮动．运用这一工作模式解释了器件的各类新工作特性，并且提出了利用这种量子阶控制极来制作新的异质谷间转移电子三极管的可能性     

Theory of negative-conductance amplification and of Gunn instabilities in "two-valley" semiconductors

A theory of negative-conductance amplification and of Gunn-effect oscillation in good agreement with experimental observations is developed for "two-valley" semiconductors such as GaAs and InP. The theory is based upon a conduction-band model in which the relative populations of two valleys of vastly different mobility are determined by the average electron temperature, the latter being described by energy transport equations. Numerical computer solutions of the dynamic equations identify different modes of sample behavior and give a clear indication of the microscopic physical processes relevant to each.     

能带混合量子阱的触发功能和异质谷间转移电子放大器件的研究

运用MonteCarlo理论模拟、二极管除穿伏安特性、器件振荡性能和射频输入信号激励下的放大功能研究了异质谷间转移电子器件中能带混合量子阱的触发功能。理论和实验研究发现，当能带混合量子讲中没有产生足够的异质谷间转移电子效应时，即使有源层中加有足够的电场仍然不能产生振荡。异质谷间转移电子效应成为器件进行射频工作的必要条件。在适当设计的器件中，运用输入射频信号也能激励异质谷间转移电子效应而触发输出放大信号。应用这一原理研制成8mm波段工作的稳态放大器，解决了二极管稳态放大器中的自激振荡问题。最后讨论了利用能带混合量子讲的触发功能来制作新的三端器件和各类功能器件的可能性。     

Transport equations for electrons in two-valley semiconductors

Transport equations are derived for particles, momentum, and energy of electrons in a semiconductor with two distinct valleys in the conduction band, such as GaAs. Care is taken to state and discuss the assumptions which are made in the derivation. The collision processes are expressed in terms of relaxation times. The accuracy is improved by considering these to depend on the average kinetic energy rather than the electron temperature. Other transport equations used in the literature are discussed, and shown to be incomplete and inaccurate in many cases. In particular, the usual assumption that the mobility and diffusion constant depend locally on the electric field strength is shown to be incorrect. Rather, these quantities should be taken as functions of the local average velocity of electrons in the lower valley.     

Hydrodynamic hot-electron transport simulation based on the Monte Carlo method

A hydrodynamic hot electron model is used to study electron transport through a submicron N⁺ --- N --- N⁺ GaAs structure. This study is used to investigate improvements which the unique features of this model offer to analysis of devices operating under nonstationary transport conditions. The model is based upon semiclassical “hydrodynamic” conservation equations for the average carrier density, momentum and energy. The general model includes particle relaxation times, momentum relaxation times, energy relaxation times, electron temperature tensors and heat flow vectors as a function of average carrier energy for the Γ, X and L valleys of GaAs. For this study, we utilized a simplified single electron gas version of our model to clearly reveal the impact of the nonstationary terms in the model. Results from both a drift-diffusion model approach and a Monte Carlo analysis are used to show the relative accuracy and facility this new model offers for investigating practical submicron device structures operating under realistic conditions.     

Studies of aluminum Schottky barrier gate annealing on GaAs FET structures

Controlled annealing experiments on special GaAs FET structures have been used to assess the integrity of Al/nGaAs Schottky barrier gates. Metallurgical properties of the Al/nGaAs interface were analyzed using microspot Auger electron spectroscopy. Results indicate interdiffusion between Al and GaAs at the baseline annealing temperature of 275°C. At this temperature the three terminal static FET parameters were unaffected by the annealing, but the two terminal gate/source static characteristic was somewhat improved over unannealed control FETs. Annealing the Al gate up to 450°C does not appear to be harmful to the gate/source two terminal static characteristic although at this temperature three terminal static FET characteristics are severely degraded. The Al/nGaAs interface is assessed as being both metallurgically and electrically stable when employed in inert ambient environments up to 275°C for 24 hr.     

Energy-balance model for Gunn domains

Domains are simulated using a new model in which the electron transport and relaxation coefficients depend on the mean energies of the electrons in the valleys, which are deduced from the energy balance within the domain. In GaAs, the accumulation layers are narrowed by cooling effects.     

InGaAs／GaAs异质结构材料及器件应用

概述了ＩｎＧａＡｓ／ＧａＡｓ异质结构材料用于制作微波器件的优越性，叙述了材料的ＭＢＥ生长、输运特性和掺杂分布，以及用于制作Ｋｕ波段低噪声高增益ＨＦＥＴ的结果：栅长０．５μｍ，１２ＧＨｚ下噪声系数０．９３ｄＢ，相关增益９ｄＢ。     

半导体异质结构中的谷间电子转移效应(英文)

The transferred electron effect between different valleys in AlGaAs/ GaAs/AlGaAs heterostructure is studied using the one-band two-valley model in this paper. Taking the contributions from a varied electric field and the band offset and the coupling between different valleys at every heterojunction interface into account, the formulas for calculating the tunnelling probability and current are derived. The tunnelling probabilities and currents for various heterostructures, alloy components and electric fields have been calculated. The dependence of transferred electron effect on the heterojunction interface, the band structures of the well and barrier materials, and the electric field is discussed. The computed tunnelling current agrees with the experimental results, and so the effectiveness of this model in the researching of many-valley system is demonstrated. Furthermore, the difference between this transferred electron effect and the well known Gunn effect is pointed out and its application in the developing of semiconductor devices is discussed.     

Degradation mechanisms induced by high current density in Al-gate GaAs MESFET's

High gate-current density, which can arise due to RF overdrive, induces two degradation mechanisms in Al-gate power GaAs MESFET's: 1) high current density through the Al-gate finger section causes gate interruption at the beginning of the metal stripe due to electromigration and makes it impossible to reach the pinchoff condition; 2) high current density through the Schottky junction promotes a fast Al/GaAs interaction, causing an increase in the Schottky-barrier height from 0.80 to 0.96 eV owing to the formation of an AlxGa1-xAs interfacial layer. Al/GaAs interaction appears to be enhanced by the electron current at a given temperature.