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.     

Si/ SiGe/ Si HBT 的直流特性和低频噪声

在对Si/SiGe/Si HBT及其Si兼容工艺的研究基础上，研制成功低噪声Si/SiGe/Si HBT，测试和分析了它的直流特性和低频噪声特性，为具有更好的低噪声性能的Si/SiGe/Si HBT的研究建立了基础。     

SiGe HBT高频噪声等效模型研究

对硅锗异质结双极型晶体管（SiGe HBT）等效高频噪声模型进行了研究,在建模过程中,SiGe HBT的等效电路为小信号准静态等效电路,使用二端口网络噪声相关矩阵技术从实测噪声参数提取基极和发射极的散粒噪声,提取结果与几种散粒噪声模型进行对比分析,重点研究半经验模型建立过程,对半经验模型与常用的噪声模型使用CAD仿真验证,结果表明了半经验模型的有效性、更具准确性,该半经验模型能够用到不同工艺SiGe HBT的高频噪声模拟。     

版图尺寸对SiGe/Si HBT高频噪声特性的影响

从实验上研究了版图尺寸对Si/SiGe HBT高频噪声特性的影响。结果表明,在现有工艺条件下,减少外基区电阻(即减少发射极与基区间距),对降低高频噪声很显著。增加基极条数、增加条长也可减少基极电阻,降低高频噪声。发射极条宽从2μm减少为1μm,对噪声的改善很有限。对1μm或2μm条宽,40μm条长的5个基极条或9个基极条的SiGe HBT,在片测试表明,频率从0.4 GHz增加到1.2 GHz,噪声系数在2.5~4.6 dB之间变化。     

SiGe HBT高频噪声特性研究

对SiGe HBT的高频噪声进行了模拟.频率f、载流子正向延迟时间τF、集电极电流等因素都对高频噪声有影响.当频率高于高频转角频率时,最小噪声系数NFmin随着频率的增大而线性增大,而不是与f2成正比关系,且NFmin随着集电极电流的增大先减小后增大.结果表明,噪声最小时的最佳偏置电流所对应的特征频率fT并不是最大特征频率,约为最大特征频率的50%.     

SiGe/Si HBT高频噪声特性研究

基于器件Y参数,对Si/Si1-xGexHBT的高频噪声进行了模拟。Si/Si1-xGexHBT的高频最小噪声系数随Ge组份x的增加而减小。与Si BJT相比,Si/SiGe HBT具有优异的高频噪声特性。     

混合模式电应力损伤对SiGe HBT器件1/f噪声特性的影响研究

研究了混合模式应力损伤对SiGe HBT器件直流电性能的影响,对比了混合模式损伤前后器件1/f噪声特性的变化。结果表明,在SiGe HBT器件中,混合模式损伤在Si/SiO₂界面产生界面态缺陷P_b,导致小注入下基极电流增加;H原子对多晶硅晶界悬挂键的钝化作用引起中等注入区基极电流减小,导致电流增益增强。混合模式损伤缺陷位于硅禁带宽度内本征费米能级附近,虽然使基区SRH复合电流增加,却不会改变器件的低频噪声特性。     

红外热像仪时间噪声测量技术研究

在对红外热像仪的测量中,噪声是评价红外热像仪性能的主要参数。噪声参数包括时间域噪声和空间域噪声,时间域噪声可分为高频时间噪声和低频时间噪声(即1/f噪声);空间域噪声可分为高频空间噪声(即固定模式噪声FPN)和低频空间噪声(非均匀性噪声)。对高频时间噪声和低频时间噪声进行了严格的区分和定义;给出了在短时间内忽略低频时间噪声时高频噪声NETD的计算模型;在不忽略低频时间噪声时计算高频噪声等效温差的数学计算模型和测量方法;对高频时间域NETD测量结果进行了不确定度分析与评价。     

射频Si/SiGe/Si HBT的研究

在Si／SiGe／SiHBT与Si工艺兼容的研究基础上，对射频Si／SiGe／SiHBT的射频特性和制备工艺进行了研究，分析了与器件结构有关的关键参数寄生电容和寄生电阻与Si／SiGe/Si HBT的特征频率fT和最高振荡频率fmax的关系，成功地制备了fT为2．5CHz、fmax为2．3GHz的射频Si／SiGe／SiHBT，为具有更好的射频性能的Si／SiGe／Si HBT的研究建立了基础。     

Ge组分对SiGe HBT主要电学特性的影响

采用SiGe异质结结构提高晶体管的性能,分析了Ge对器件电流增益和频率特性提高的物理机制.综合考虑了Si1-xGex薄膜的稳定性、工艺特点和器件结构对Ge含量以及分布的要求和Ge组分的设计及其对器件电学特性的影响.从理论上推算了SiGe HBT的β和fT等主要特性参数,Ge的引入以及Ge的分布情况对提高这些参数有着显著的影响.Ge的引入对晶体管主要特性参数的提高使得SiGe HBT技术在微波射频等高频电子领域可以有更重要的应用前景.     

Ionizing radiation tolerance and low-frequency noise degradation inUHV/CVD SiGe HBT's

The effect of ionizing radiation on both the electrical and 1/f noise characteristics of advanced UHV/CVD SiGe HBT's is reported for the first time. Only minor degradation in the current-voltage characteristics of both SiGe HBT's and Si BJT's is observed after total radiation dose exposure of 2.0 Mrad(Si) of gamma-radiation. The observed immunity to ionizing radiation exposure suggests that these SiGe HBT's are well suited for many applications requiring radiation tolerance. We have also observed the appearance of ionizing-radiation-induced generation-recombination (G/R) noise in some of these SiGe HBT's     

Noise in SiGe HBT RF Technology: Physics, Modeling, and Circuit Implications

This paper presents an overview of the physics, modeling, and circuit implications of RF broad-band noise, low-frequency noise, and oscillator phase noise in SiGe heterojunction bipolar transistor (HBT) RF technology. The ability to simultaneously achieve high cutoff frequency (f/sub T/), low base resistance (r/sub b/), and high current gain (/spl beta/) using Si processing underlies the low levels of low-frequency 1/f noise, RF noise, and phase noise of SiGe HBTs. We first examine the RF noise sources in SiGe HBTs and the RF noise parameters as a function of SiGe profile design, transistor biasing, sizing, and operating frequency, and then show a low-noise amplifier design example to bridge the gap between device and circuit level understandings. We then examine the low-frequency noise in SiGe HBTs and develop a methodology to determine the highest tolerable low-frequency 1/f noise for a given RF application. The upconversion of 1/f noise, base resistance thermal noise, and shot noises to phase noise is examined using circuit simulations, which show that the phase noise corner frequency in SiGe HBT oscillators is typically much smaller than the 1/f corner frequency measured under dc biasing. The implications of SiGe profile design, transistor sizing, biasing, and technology scaling are examined for all three types of noises.     

Low-frequency noise in UHV/CVD epitaxial Si and SiGe bipolartransistors

In this work a comprehensive investigation of low-frequency noise in ultrahigh vacuum/chemical vapor deposition (UHV/CVD) Si and SiGe bipolar transistors is presented. The magnitude of the noise of SiGe transistors is found to be comparable to the Si devices for the identical profile, geometry, and bias. A comparison with different technologies demonstrates that the SiGe devices have excellent noise properties compared to AlGaAs/GaAs heterojunction bipolar transistors (HBT's) and conventional Si bipolar junction transistors (BJT's). Results from different bias configurations show that the 1/f base noise source is dominant in these devices. The combination of a 1/Area dependence on geometry and near quadratic dependence on base current indicates that the 1/f noise sources are homogeneously distributed over the entire emitter area and are probably located at the polysilicon-Si interface. Generation/recombination (Gm) noise and random telegraph signal (RTS) noise was observed in selected Si and SiGe devices. The bias dependence and temperature measurements suggest that these G/R centers are located in the base-emitter space charge region. The activation energies of the G/R traps participating in these noise processes were found to be within 250 meV of the conduction and valence band edges     

基于SOS/SOI绝缘衬底的Si/SiGe HBT设计

着重讨论了衬底阻抗对HBT器件频率性能的劣化机制。基于双口网络理论，定量分析了fT和fm与衬底电阻率的关系；采用SOS／SOI绝缘衬底和自行设计的岛型膈离方法，抑制了绝大多数容性寄生参数；同时，围绕绝缘衬底进行Si／Si GeHBT的横向／纵向结构设计，开发出发射极自对准工艺方法，用于降低接触电阻和一定特征尺寸下的结面积，提高了HBT的频率性能。     

Low 1/f noise characteristics of AlGaAs/GaAs heterojunction bipolartransistor with electrically abrupt emitter-base junction

It is shown that the use of an electrically abrupt emitter-base junction considerably reduces the 1/f noise of self-aligned AlGaAs/GaAs heterojunction bipolar transistor (HBT). Although this device does not have depleted AlGaAs ledge passivation layer, the low-frequency noise spectra show a very low 1/f noise corner frequency of less than 10 kHz, which is much lower than previously reported value of about 100 kHz from conventional passivated or unpassivated AlGaAs/GaAs HBT's. Except for a residual generation-recombination (g-r) noise component, the noise power is comparable to that of Si BJT. It is also found that the low-frequency noise power of the AlGaAs/GaAs HBT is proportional to the extrinsic GaAs base surface recombination current square. Unlike the other HBT's reported, the noise sources associated with interface state and emitter-base (E-B) space charge region recombination are not significant for our device     

SiGe/Si HBT低频噪声特性研究

对Si/Si1-xGexHBT的低频噪声进行了模拟。频率、基极电流、集电极电流、发射极几何尺寸(面积、条长)、Ge组份x、温度等诸多因素都对低频噪声有影响。模拟结果表明,Si/SiGeHBT具有优异的低频噪声特性。     

Hot electron and hot hole degradation of UHV/CVD SiGe HBT's

We investigate the degradation in current gain and low-frequency noise of SiGe HBT's under reverse emitter-base stress due to hot electrons (forward-collector stress) and hot holes (open-collector stress). Contrary to previous assumptions we show that hot electrons and hot holes with the same kinetic energy generate different amounts of traps and hence have a different impact on device degradation. These results suggest that the accuracy of using forward-collector stress as an acceleration tool and reliability predictor must be carefully examined. We also present, for the first time, the effect of Ge profile shape on the reliability of SiGe HBT's, as well as discuss measurements on SiGe HBT's as a function of device geometry and temperature