共查询到19条相似文献,搜索用时 921 毫秒
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双极器件中硅基区和锗硅基区的禁带变窄量 总被引:1,自引:0,他引:1
采用一种新的方法计算双极器件中离子注 B硅基区和原位掺 B的锗硅基区禁带变窄量 .在器件基区的少子迁移率、多子迁移率和方块电阻已知的情况下 ,应用这种方法只需测量室温和液氮温度下的电学特性就可以获得禁带变窄量 .这种方法从双极晶体管的集电极电流公式出发 ,利用 VBE做自变量 ,在室温和液氮温度下测量器件的Gum mel图 ,选取 ln IC随 VBE变化最为线性的一部分读出 VBE及相应的 IC数值 ,获得两条 VBE- ln IC直线 ,通过求解两条直线的交点可以计算出基区的禁带变窄量ΔEG.利用这种方法测试了硅双极器件和锗硅基区双极器件 ,其基区禁带变窄量分别为 相似文献
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采用一种新的方法计算双极器件中离子注B硅基区和原位掺B的锗硅基区禁带变窄量.在器件基区的少子迁移率、多子迁移率和方块电阻已知的情况下,应用这种方法只需测量室温和液氮温度下的电学特性就可以获得禁带变窄量.这种方法从双极晶体管的集电极电流公式出发,利用VBE做自变量,在室温和液氮温度下测量器件的Gummel图,选取lnIC随VBE变化最为线性的一部分读出VBE及相应的IC数值,获得两条VBE-lnIC直线,通过求解两条直线的交点可以计算出基区的禁带变窄量ΔEG.利用这种方法测试了硅双极器件和锗硅基区双极器件,其基区禁带变窄量分别为41meV和125meV,这个测量结果与文献中的数值符合较好. 相似文献
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通过对电流增益温度模型的分析,表明发射区重掺杂引起的禁带变窄效应是低温下双极晶体管电流增益衰变的主要原因,提出了用温度比例因子设计低温基区轻掺杂双极晶体管的新设计方法,计算机模拟表明结果良好。 相似文献
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<正>近年来,低温(77K)微电子器件和电路的研究得到了国际上广泛重视,已成为半导体学科十分重要和活跃的领域之一.本文建立了低温下双极型晶体管电流增益和基区杂质浓度的新关系,这将成为低温双极型晶体管设计的重要理论依据.以n~+pn型晶体管为例进行分析,当基区杂质浓度N_B小于N_0=1×10~(17)cm~(-3)时,基区中无禁带变窄效应的存在,此时电流增益H_(FE)将随基区杂质浓度N_B上升而下降. 相似文献
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相对于同质结晶体管,异质结双极晶体管(HBT)由于异质结的存在,电流增益不再主要由发射区和基区掺杂浓度比来决定,因此可以通过增加基区掺杂浓度来降低基区电阻,提高频率响应,降低噪声系数,但基区掺杂浓度对器件热特性影响的研究却很少。以多指SiGeHBT的热电反馈模型为基础,利用自洽迭代法分析了基区重掺杂对器件集电极电流密度和发射极指温度的影响。通过研究发现,随着基区浓度的增加,SiGe HBT将发生禁带宽度变窄,基区反向注入发射区的空穴电流增大;同时,基区少子俄歇复合增强,这些都将减小集电极电流密度,降低发射极指温度,从而抑制发射极指热电正反馈,提高器件的热稳定性。 相似文献
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基区杂质外扩对SiGe/Si HBT低温特性的影响 总被引:1,自引:0,他引:1
SiGe/Si HBT的基区杂质在工艺过程中外扩到发射区和收集区,使得低温增益下降,提出采用适当厚度的隔离层的方法,使HBT电流增益在低温下增长。 相似文献
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本文考虑了基区复合电流,发射结空间电荷区复合电流,基区高注入引起的禁带变窄效应,Early效应,基区和发射区电导调制效应,有效基区展宽效应以及发射区电流集边效应,定量地模拟了硅双极晶体管电流增益在77K和300K时与集电极电流的关系,并且与实验结果相吻合,计算还表明在低温77K时,电流增益的大注入效应由基区电导调制效应和发射区电流集边效应决定,而在300K时则由有效基区展宽效应决定。 相似文献
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Application of the Monte Carlo technique to analyze electron and hole transport in bulk Si0.8Ge0.2 and strained Si 0.8Ge0.2/Si is discussed. The computed minority- and majority-carrier transport properties were used in a comprehensive small-signal model to evaluate the high-frequency performance of a state-of-the-art n-p-n heterostructure bipolar transistors (HBT) fabricated with SiGe as the base material. The valence band discontinuity of a SiGe-base HBT reverses the degradation in emitter injection efficiency caused by bandgap narrowing in the base, and permits a higher ratio of base doping to emitter doping than would be practical for a bipolar transistor. Any degradative effect of increased base doping on electron and hole mobilities is offset by improved transport in the strained SiGe base, resulting in a marked decrease in the base resistance and base transit time. Compared to the Si BJT, the use of Si0.8Ge0.2 for the base region of an HBT leads to significant improvements in low-frequency common emitter current gain, low-frequency unilateral power gain, and maximum oscillation frequency 相似文献
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测量了Si/SiGe HBT在23~260℃温度范围内的Gummel图、理想因子n、不同基极电流下的发射结电压VBE、电流增益β、共发射极输出特性,以及Early电压VA的变化情况。结果表明,随电流和温度的增加,β减少,VBE随温度的变化率dVBE/dT小于同质结Si BJT。在高集电极-发射极电压和大电流下,在输出特性曲线上观察到了负微分电阻(NDR)特性。结果还显示,电流增益-Early电压积与温度的倒数(1/T)呈线性关系,这对模拟电路应用是很重要和有用的。 相似文献
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本文用RBS,AES,TEM和X射线衍射等实验方法,分析比较了Ni/Si,Pt/Si,Ir/Si系统在室温下As离子混合和热退火的行为.得出在Ni/Si系统中,硅混合量Q_(s1)与剂量Φ的平方根成正比,形成Ni_2Si相.在Pt/Si系中,硅混合量也与剂量的平方根成正比,先后形成Pt_3Si和Pt_2Si相.对Ir/Si系,Q_(s1)与Φ则是线性关系:Q_(s1)=aΦ+b,未测到化学相.实验表明:离子束混合能大大增强金属和硅化物的化学反应.在离子混合和退火形成硅化物的过程中,注入杂质As的分布有显著变化. 相似文献
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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。 相似文献
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Si/SiGe/Si HBT的优化设计 总被引:2,自引:0,他引:2
给出了常温和低温Si/SiGe/SiHBT的设计原则,并进行了讨论。指出了低温和室温HBT设计上的差异。这些原则可用于设计特定要求的Si/SiGe/SiHBT。 相似文献
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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。 相似文献
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Matutinovic-Krstelj Z. Venkataraman V. Prinz E.J. Sturm J.C. Magee C.W. 《Electron Devices, IEEE Transactions on》1996,43(3):457-466
This paper presents a comprehensive study of the effects of heavy doping and germanium in the base on the dc performance of Si/Si1-x Gex/Si npn Heterojunction Bipolar Transistors (HBTs). The lateral drift mobility of holes in heavily doped epitaxial SiGe bases affects the base sheet resistance while the effective bandgap is crucial for the vertical minority carrier transport. The devices used in this study were Si1-xGex npn HBTs with flat Ge and B profiles in the base grown by Rapid Thermal Chemical Vapor Deposition (RTCVD). Hall and drift lateral hole mobilities were measured in a wide range of dopings and Ge concentrations. The drift mobility was indirectly measured based on measured sheet resistivity and SIMS measurements, and no clear Ge dependence was found. The Hall scattering factor is less than unity and decreases with increasing Ge concentration. The effective bandgap narrowing, including doping and Ge effects, was extracted from the room temperature collector current measurements over a wide range of Ge and heavy doping for the first time. We have observed bandgap narrowing due to heavy base doping which is, to first order, independent of Ge concentration, but less than that observed in silicon, due to the effect of a lower density of states. A model for the collector current enhancement with respect to Si devices versus base sheet resistance is presented 相似文献
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Kumiko Asami Kazushi Miki Kunihiro Sakamoto Tsunenori Sakamoto Shun-Ichi Gonda 《Journal of Electronic Materials》1992,21(2):223-226
The thermal stability of Si/Gen/Si(001) heterostructures includingn = 1, 6, 20, and 100 monolayers (ML’s) is studied in connection with their electronic structures through the measurement of
photoreflectance (PR). The PR spectra are observed at 90 K over the energy range 0.85–4.0 eV. Comparing the PR signals of
Si/Ge
n
/Si(001) heterostructures before and after thermal annealing at 600° C, it is found that the samples with less than 6 ML Ge
show no change whereas those with more than 20 ML Ge show large changes. The result suggests that Si/Ge
n
/Si heterostructures with Ge layer thickness less than 6 ML’s are thermally stable. For the heterostructures with 20 and 100
ML Ge, the relaxation of strain in the Ge layer is found to occur from the PR spectra ofE
0(Ge),E
1(Ge) andE
1 +Δ
1(Ge), andE
1(Si). 相似文献