微波功率SiGe HBT的温度特性

通过研究SiGe异质结双极型晶体管(HBT)的温度特性,发现SiGe HBT的发射结正向电压随温度的变化率小于同质结Si双极型晶体管(BJT).在提高器件或电路热稳定性时,SiGe HBT可以使用比Si BJT更小的镇流电阻.同时SiGe HBT共发射级输出特性曲线在高电压大电流下具有负阻特性,而负阻效应的存在可以有效地抑制器件的热不稳定性效应,从而在温度特性方面证明了SiGe HBT更适合于微波功率器件.     

微波功率SiGe HBT的温度特性

通过研究SiGe异质结双极型晶体管(HBT)的温度特性,发现SiGe HBT的发射结正向电压随温度的变化率小于同质结Si双极型晶体管(BJT).在提高器件或电路热稳定性时,SiGe HBT可以使用比Si BJT更小的镇流电阻.同时SiGe HBT共发射级输出特性曲线在高电压大电流下具有负阻特性,而负阻效应的存在可以有效地抑制器件的热不稳定性效应,从而在温度特性方面证明了SiGe HBT更适合于微波功率器件.     

微波功率SiGe HBT的温度特性

通过研究SiGe异质结双极型晶体管(HBT)的温度特性，发现SiGe HBT的发射结正向电压随温度的变化率小于同质结Si双极型晶体管(BJT). 在提高器件或电路热稳定性时，SiGe HBT可以使用比Si BJT更小的镇流电阻.同时SiGe HBT共发射级输出特性曲线在高电压大电流下具有负阻特性，而负阻效应的存在可以有效地抑制器件的热不稳定性效应，从而在温度特性方面证明了SiGe HBT更适合于微波功率器件.     

浅谈半导体器件在移动电话中的应用

在移动电话中作为RF功率部分,大量使用各种半导体分立器件,或由它们构成的微波单片集成电路(MMIC)。在该领域GaAs和Si的应用几乎并驾齐驱。具体而言,有Si双极晶体管、Si MOSFET、Si/Ge HBT、GaAs、MESFET、GaAs P-HEMT和GaAs HBT等。     

SiGe HBT低频噪声PSPICE模拟分析

对SiGe HBT低频噪声的各噪声源进行了较全面的分析,据此建立了SPICE噪声等效电路模型,进一步用PSPICE软件对SiGe HBT的低频噪声特性进行了仿真模拟.研究了频率、基极电阻、工作电流和温度等因素对低频噪声的影响.模拟结果表明,相较于Si BJT和GaAs HBT,SiGe HBT具有更好的低频噪声特性;在低频范围内,可通过减小基极电阻、减小工作电流密度或减小发射极面积、降低器件的工作温度等措施来有效改善SiGe HBT的低频噪声特性.所得结果对SiGe HBT的设计和应用有重要意义.     

与Si 工艺兼容的Si/ SiGe/ Si HBT 研究

我们对Si/SiGe/Si HBT及其Si兼容工艺进行了研究,在研究了一些关键的单项工艺的基础上,提出了五个高速Si/SiGe/Si HBT结构和一个低噪声Si/SiGe/Si HBT结构,并已研制成功台面结构Si/SiGe/Si HBT和低噪声Si/SiGe/Si HBT,为进一步高指标的Si/SiGe/Si HBT的研究建立了基础。     

SiGe HBT技术及其在超高速光纤通信电路中的应用

超高速通信集成电路必须满足高速率、低成本、低功耗和低噪声等指标要求。因为本文介绍了SiGe HBT的一些重要特性,SiGe HBT和Si基工艺兼容,能有效的将CMOS电路集成到一起,具有和Si工艺一样的低成本,而性能指标却能和GaAs、InP等媲美,笔者用IBM公司0．5μm SiGe BiCMOS HBT工艺设计了一个10Gbit／s的光接收机限幅放大器。     

微波大功率SiGe HBT的研究进展及其应用

文章论述了SiGe异质结双极晶体管(HBT)在微波功率领域应用的优势,详细介绍了微波功率SiGe HBT的结构设计方法,以及主要影响器件性能的材料和结构因素,评述了其最新进展及今后发展方向.     

SiGe HBT和Si BJT的γ射线辐照效应比较

比较了经剂量为400 krad(Si)的Y射线辐照后SiGe HBT和Si BJT直流电学性能的变化.通常SiGe HBT辐照后的Ib增加,Ic下降,直流放大倍数变化很小;Si BJT辐照后的Ib增加,而Ic通常也增加,并且变化幅度很大,直流放大倍数明显下降,相同剂量下变化幅度比SiGe HBT约高一个量级.表明SiGe HBT比Si BJT有更好的抗辐照性能,并对辐照导致的电特性的变化原因进行了初步解释.     

多发射极条功率SiGe HBT的热电耦合与优化设计

利用自洽迭代数值计算方法,对多发射极微波功率SiGe HBT芯片热电耦合特性进行了模拟和分析。结果表明,通过对晶体管发射极条长、条间距的调整,可以有效地改善芯片温度分布的不均匀性,提高晶体管的热稳定性和功率处理能力。     

Integrated circuit technology options for RFICs-present status andfuture directions

This paper will summarize the technology tradeoffs that are involved in the implementation of radio frequency integrated circuits for wireless communications. Radio transceiver circuits have a very broad range of requirements-including noise figure, linearity, gain, phase noise, and power dissipation. The advantages and disadvantages of each of the competing technologies-Si CMOS and bipolar junction transistors (BJTs), Si/SiGe HBTs and GaAs MESFETs, PHEMTS and HBTs will be examined in light of these requirements     

Thermal design studies of high-power heterojunction bipolartransistors

A theoretical thermoelectro-feedback model has been developed for the thermal design of high-power GaAlAs/GaAs heterojunction bipolar transistors (HBTs). The power-handling capability, thermal instability, junction temperature, and current distributions of HBTs with multiple emitter fingers have been numerically studied. The calculated results indicate that power HBTs on Si substrates (or with Si as the collector) have excellent potential power performance and reliability. The power-handling capability on Si is 3.5 and 2.7 times as large as that on GaAs and InP substrates, respectively. The peak junction temperature and temperature difference on the chip decrease in comparison to the commonly used Si homostructure power transistor with the same geometry and power dissipation. Thereby HBTs are promising for high-speed microwave and millimeter-wave applications. It has been also found that the nonuniform distribution of junction temperature and current can be greatly improved by a ballasting technique that uses unequal-valued emitter resistors     

Electrical stress effect on RF power characteristics of SiGe hetero-junction bipolar transistors

In this paper, we investigate the electrical stress effects on both the high-frequency and RF power characteristics of Si/SiGe HBTs. Simultaneously applying a high collector current density and a high collector–base voltage upon the Si/SiGe HBTs, their hot carriers will induce device performance degradation. This stress condition is similar to the DC bias conditions of a current source RF power amplifier, and is termed as a “mixed-mode” stress. We find that not only the maximum oscillation frequency but also the output power performance of Si/SiGe HBTs are suffered by this electrical stress. In addition, the degradations of high-frequency and power characteristics are also worse under a constant base-current measurement than those under a constant collector-current measurement. Finally, we developed a commercial large-signal model to examine the degradations of the parasitic resistances and ideality factors of base and collector currents to explain the RF power and linearity degradations.     

Performance comparison of state-of-the-art heterojunction bipolar devices (HBT) based on AlGaAs/GaAs, Si/SiGe and InGaAs/InP

This paper presents a comprehensive comparison of three state-of-the-art heterojunction bipolar transistors (HBTs); the AlGaAs/GaAs HBT, the Si/SiGe HBT and the InGaAs/InP HBT. Our aim in this paper is to find the potentials and limitations of these devices and analyze them under common Figure of Merit (FOM) definitions as well as to make a meaningful comparison which is necessary for a technology choice especially in RF-circuit and system level applications such as power amplifier, low noise amplifier circuits and transceiver/receiver systems. Simulation of an HBT device with an HBT model instead of traditional BJT models is also presented for the AlGaAs/GaAs HBT. To the best of our knowledge, this work covers the most extensive FOM analysis for these devices such as I-V behavior, stability, power gain analysis, characteristic frequencies and minimum noise figure. DC and bias point simulations of the devices are performed using Agilent's ADS design tool and a comparison is given for a wide range of FOM specifications. Based on our literature survey and simulation results, we have concluded that GaAs based HBTs are suitable for high-power applications due to their high-breakdown voltages, SiGe based HBTs are promising for low noise applications due to their low noise figures and InP will be the choice if very high-data rates is of primary importance since InP based HBT transistors have superior material properties leading to Terahertz frequency operation.     

SiGe HBT发射区台面自中止腐蚀技术研究

台面结构SiGe/Si异质结晶体管制作过程中,发射区台面形成尤为关键。由于干法刻蚀速率难以精确控制,且易损伤SiGe外基区表面,SiGe自中止湿法腐蚀成为台面结构SiGe/Si异质结晶体管制作过程中的优选工艺。分析了SiGe自中止腐蚀的反应机理,对腐蚀条件包括掩蔽膜的选取,温度、超声等因素对腐蚀速率及均匀性的影响进行摸索,取得了较好结果,最终采用该技术完成了SiGe/Si npn型异质结晶体管的制作,测得其电流增益β>80,对采用台面结构制造SiGe/Si HBT具有一定参考价值。     

On the operation configuration of SiGe HBTs based on power gain analysis

The power gain difference, under different device stability conditions, between common-emitter (CE) and common-base (CB) bipolar junction transistors (BJT) is analyzed comprehensively. The analysis reveals that the CB configuration offers higher maximum available power gain than the CE configuration in the device's high operation frequency range, while the inverse relation holds in the very low frequency range. In the intermediate frequency range, the base resistance value, mainly affected by the base doping concentration, determines which configuration offers higher maximum stable power gain (MSG). These analyses have explicit implications on the operation configurations of SiGe heterojunction bipolar transistors (HBTs). Employing a typical doping profile of Si bipolar junction transistors with a trapezoidal Ge profile in SiGe HBTs usually results in a larger base resistance than the emitter resistance. For these devices, the CE configuration exhibits higher MSG than the CB configuration. Employing a higher base doping concentration than the emitter with a box-type Ge profile considerably reduces the base resistance and thus favors the CB configuration for power amplification in this frequency range. The analysis are quantitatively verified with simulation and measurement results from SiGe HBTs of representative Ge and base doping profiles.     

Measurement of collector-base junction avalanche multiplicationeffects in advanced UHV/CVD SiGe HBT's

This paper presents measurements of the avalanche multiplication factor (M-1) in SiGe HBTs using a new technique capable of separating the avalanche multiplication and Early effect contributions to the increase of collector current with collector-base bias, as well as allowing safe measurements at practical current densities. The impact of collector doping, current density, Ge profile, and operation temperature are reported for the first time using measured and simulated results from a production quality UHV/CVD SiGe HBT technology. Limitations of the technique in the presence of significant self-heating are discussed. By turning on the secondary hole impact ionization, we revealed the difference in impact ionization between strained SiGe and Si in the presence of the “dead space” effect. Despite its smaller bandgap, the compressively strained SiGe layer shows an apparent decrease in the secondary hole impact ionization rate compared to Si     

Analytical modelling of current gain and frequency characteristics under high injection levels in Si/SiGe heterojunction bipolar transistors at 77 and 300 K

This paper reports an analytical modelling of current gain and frequency characteristics in Si/SiGe heterojunction bipolar transistors (HBTs) at 77 and 300 K. Important transistor parameters, such as current gain, transconductance, cutoff frequency and maximum oscillation frequency are calculated as a function of Ge concentration in the base under different injection levels. The main physical mechanisms for the current and cutoff frequency rolloff at high injection levels are also analyzed. It shows that the high-level injection effect is more pronounced in the SiGe HBTs as a result of the increasing minority carrier concentration in the base and the Ge concentration and distribution will have a decisive influence of device performance. The results may provide a basis for the design of low temperature operation SiGe HBTs.