InP异质结晶体管

提出了准平面构成的InP HBT新结构，用Si离子注入在半绝缘InP：Fe上形成隐埋n型区来代替通常采用的外延n型收集区，可有效降低器件的高度，减小寄生参数，提高器件的可靠性，测量结果表明，晶体管的hfe=100,VCE=3-4V,fT=10GHz。     

InP异质结晶体管

提出了准平面构成的InP HBT新结构。用Si离子注入在半绝缘In P:Fe上形成隐埋n型区来代替通常采用的外延n型收集区,可有效降低器件的高度,减小寄生参数,提高器件的可靠性。测量结果表明,晶体管的h_(fe)=100,V_(CE)=3～4V,f_T=10GHz。     

选择性掺杂异质结晶体管

利用国产MBE系统外延生长的调制掺杂材料,试制出选择性掺杂晶体管或高电子迁移率晶体管(HEMT)。准增强型器件的跨导为60～90mS/mm。有些器件发现有负阻,跨导达190mS/mm。     

硅异质结晶体管的试制

本文较详细地分析了Si/α-Si异质结晶体管(HBT)的微波性能和工艺优点,简述了工艺过程,初步实验结果证实:Si/α-Si HBT具有较好的小电流特性,晶体管的h_(fe)=12(V_(CE=10V,I_C=1mA),BV_(CEO)=20V。     

SiGe异质结晶体管技术的发展

以全球信息产业需求及技术发展为背景,回顾了以能带工程为基础的、在现代通信领域得到广泛应用的SiGe异质结晶体管技术的发展历程。介绍了分子束外延、超高真空化学气象淀积和常压化学气象淀积3种典型的SiGe外延技术并对比了这三种技术的优缺点。在此基础上,对SiGe HBT技术进行了分析总结并列举了其典型技术应用。以IBM的SiGe BiCMOS技术为例,介绍了目前主流的SiGe异质结晶体管技术-SiGe BiCMOS技术的研究现状及典型技术产品。最后对正在发展中的SiGe FET技术做了简要介绍。在回顾了SiGe异质结晶体管技术发展的同时,认为未来SiGe异质结晶体管技术的提高将主要依赖于超薄SiGe基区外延技术。     

SiGe异质结晶体管频率特性模型研究

在分析载流子输运和分布的基础上，建立了SiGe异质结晶体管(HBT)各时间常数模型；在考虑发射结空间电荷区载流子分布和集电结势垒区存在可劝电荷的基础上，建立了SiGe HBT发射结势垒电容模型和不同电流密度下包括基区扩展效应的集电结势垒电容模型。对SiGe HBT特征频率及最高振荡频率与电流密度、Ge组分、掺杂浓度、结面积等之间的关系进行了模拟，对模拟结果进行了分析和讨论。     

与发光管集成在一起的异质结晶体管

最近,异质结光电晶体管(HPT)在响应速度和带宽方面的改进,激发了把这种器件应用到长波长光纤系统中去的兴趣。HPT噪声特性的分析表明,在使用dc偏置的应用中,带宽和信噪比可以最佳化。因为基区的信号电流是光生的,所以以前报导的大多数HPT都利用浮置基极结构,即没有基极接触。这种结构有消除基极接触电容的优点,同时也去除了提供dc偏置电流的能力,在本文中,我们介绍一种用发光二极管(LED)提供光偏置的结构,而这支发光管又和InP/InGaAs-HPT集成在同一芯片上。     

负阻异质结晶体管的模拟与实验

采用MBE方法生长了8nm基区的InGaP/GaAs双异质结材料,研制成具有负阻特性的异质结晶体管.在恒压恒流条件下均观察到了负阻特性并对其物理机制进行了讨论.推导出集电极电流Ic与VCE的关系表达式,讨论了负阻与器件结构和参数的关系.使用PSPICE模拟软件建立电路网表模型,代入推导出的IC-VCE公式进行模拟,模拟结果与器件的测量结果十分接近.     

耗尽型选择性掺杂异质结晶体管

设计和研制了耗尽型选择性掺杂异质结晶体管。外延选择性掺杂材料是由本所Fs-Ⅲ型分子束外延炉生长的。制作器件的材料在室温下,霍尔测量的电子迁移率为6500cm2/vs,二维薄层电子浓度ns=91011cm2。在77K时n=75000cm2/vs。测量了具有栅长1.21.5m,栅宽2180m耗尽型异质结器件的直流特性和器件的跨导,室温下gm=110～130ms/mm,而低温77K时,可达到200ms/mm。     

Si/SiGe异质结晶体管的参数提取与特性模拟

用实验测量和理论计算相结合的方法提取了Si/SiGe异质结晶体管的直流和高频参数,分别在PSPICE和MATLAB软件平台上模拟并分析了器件的直流和高频特性,模拟结果与实际测量的结果相吻合,表明本文的提取方法可行、参数提取结果有效.     

Submicron scaling of HBTs

The variation of heterojunction bipolar transistor (HBT) bandwidth with scaling is reviewed. High bandwidths are obtained by thinning the base and collector layers, increasing emitter current density, decreasing emitter contact resistivity, and reducing the emitter and collector junction widths. In mesa HBTs, minimum dimensions required for the base contact impose a minimum width for the collector junction, frustrating device scaling. Narrow collector junctions can be obtained by using substrate transfer or collector-undercut processes or, if contact resistivity is greatly reduced, by reducing the width of the base ohmic contacts in a mesa structure. HBTs with submicron collector junctions exhibit extremely high f_max and high gains in mm-wave ICs. Transferred-substrate HBTs have obtained 21 dB unilateral power gain at 100 GHz. If extrapolated at -20 dB/decade, the power gain cutoff frequency f_max is 1.1 THz. f_max will be less than 1 THz if unmodeled electron transport physics produce a >20 dB/decade variation in power gain at frequencies above 110 GHz. Transferred-substrate HBTs have obtained 295 GHz f_T. The substrate transfer process provides microstrip interconnects on a low-ϵ_r polymer dielectric with a electroplated gold ground plane. Important wiring parasitics, including wiring capacitance, and ground via inductance are substantially reduced. Demonstrated ICs include lumped and distributed amplifiers with bandwidths to 85 GHz and per-stage gain-bandwidth products over 400 GHz, and master-slave latches operating at 75 GHz     

Proposal and demonstration of multi-emitter HBTs

The authors have designed and tested InGaAs-InAlGaAs multi-emitter HBTs (ME-HBTs). The emitter electrodes of the transistor work as both an emitter and a base depending on their potential. A highly doped emitter layer was used for a low turn-on voltage for the collector current. Using an ME-HBT, the room-temperature operation of AND/NOR gates was tested     

Modeling and analysis of ZnSe-Ge HBTs

A Gummel-Poon model is developed for ZnSe-Ge-GaAs heterojunction bipolar transistors (HBTs). In this structure, undoped Ge spacers are placed at the emitter-base and collector-base junctions. Injected current components as well as bulk, spacer, and space charge recombination current components are modeled. Early voltage and bandgap narrowing effects are included in the model. The device performance was simulated and compared with the experimental results. The paper shows a good agreement between our model and the experimental results. The paper shows also that using spacers would improve the device performance. The advantages of this model is that it is analytical, compact, and can be easily implemented in CAD tool programs to simulate single or double HBTs with similar or dissimilar materials structure for the emitter and collector.     

Half-terahertz operation of SiGe HBTs

This letter presents the first demonstration of a silicon-germanium heterojunction bipolar transistor (SiGe HBT) capable of operation above the one-half terahertz (500 GHz) frequency. An extracted peak unity gain cutoff frequency (f/sub T/) of 510 GHz at 4.5 K was measured for a 0.12/spl times/1.0 /spl mu/m/sup 2/ SiGe HBT (352 GHz at 300 K) at a breakdown voltage BV/sub CEO/ of 1.36 V (1.47 V at 300 K), yielding an f/sub T//spl times/BV/sub CEO/ product of 693.6 GHz-V at 4.5 K (517.4 GHz-V at 300 K).     

Mechanically strained Si-SiGe HBTs

The current gain (/spl beta/=I/sub C//I/sub B/) variations of the mechanically strained Si-SiGe heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) devices are investigated experimentally and theoretically. The /spl beta/ change of HBT is found to be 4.2% and -7.8 under the biaxial compressive and tensile mechanical strain of 0.028%, respectively. For comparison, there are 4.9% and -5.0 /spl beta/ variations for BJT under the biaxial compressive and tensile mechanical strain of 0.028%, respectively. In HBT, the mechanical stress is competing with the compressive strain of SiGe base, inherited from the lattice misfit between SiGe and Si. The current change due to externally mechanical stress is the combinational effects of the dependence of the mobility and the intrinsic carrier concentration on strain.     

Nonequilibrium electron transport in HBTs

Nonequilibrium electron transport in heterojunction bipolar transistors (HBTs) becomes clearly observable as their vertical dimensions are reduced, This is the reason for the superior tradeoff relationships between the device parameters and the resultant high-speed performance of HBTs fabricated with III-V semiconductor materials. This paper reviews the hot carrier effect in the base and the velocity overshoot effect in the collector and discusses the roles these effects play in reducing carrier traveling times and improving device performance     

RF linearity characteristics of SiGe HBTs

Two-tone intermodulation in ultrahigh vacuum/chemical vapor deposition SiGe heterojunction bipolar transistors (HBTs) were analyzed using a Volterra-series-based approach that completely distinguishes individual nonlinearities. Avalanche multiplication and collector-base (CB) capacitance were shown to be the dominant nonlinearities in a single-stage common emitter amplifier. At a given I_c an optimum V_ce exists for a maximum third-order intercept point (IIP3). The IIP3 is limited by the avalanche multiplication nonlinearity at low I_c, and limited by the C_CB nonlinearity at high I_c. The decrease of the avalanche multiplication rate at high I_c is beneficial to linearity in SiGe HBTs. The IIP3 is sensitive to the biasing condition because of strong dependence of the avalanche multiplication current and CB capacitance on I_c and V_ce. The load dependence of linearity was attributed to the feedback through the CB capacitance and the avalanche multiplication in the CB junction. Implications on the optimization of the transistor biasing condition and transistor structure for improved linearity are also discussed     

微波低噪声SiGe HBT的研制

利用3μm工艺条件制得SiGeHBT(HeterojunctionBipolarTransistor),器件的特征频率达到8GHz.600MHz工作频率下的最小噪声系数为1.04dB,相关功率增益为12.6dB,1GHz工作频率下的最小噪声系数为1.9dB,相关功率增益为9dB,器件在微波无线通信领域具有很大的应用前景     

微波低噪声SiGe HBT的研制

利用3μm工艺条件制得SiGe HBT(Heterojunction Bipolar Transistor),器件的特征频率达到8GHz.600MHz工作频率下的最小噪声系数为1.04dB,相关功率增益为12.6dB,1GHz工作频率下的最小噪声系数为1.9dB,相关功率增益为9dB,器件在微波无线通信领域具有很大的应用前景.