共查询到19条相似文献,搜索用时 109 毫秒
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基于SiGe HBT(异质结双极晶体管)大信号等效电路模型,建立了SiGe HBT大信号发射结扩散电容模型和集电结扩散电容模型.该模型从SiGe HBT正反向传输电流出发,研究晶体管内可动载流子所引起的存储电荷(包括正向存储电荷和反向存储电荷)的基础上,同时考虑了厄利效应对载流子输运的影响,其物理意义清晰,拓扑结构简单。将基于大信号扩散电容模型的SiGe HBT模型嵌入PSPICE软件中,实现对SiGe HBT器件与电路的模拟分析。对该模型进行了直流特性模拟分析,直流模拟分析结果与文献报道的结果符合得较好,瞬态特性分析结果表明响应度好。 相似文献
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为了改善高压功率SiGe HBT的综合性能,应用图形外延SiGe工艺,研制出了一种新型的双多晶自对准SiGe HBT器件.相对于双台面结构的SiGe HBT而言,该结构的SiGe HBT在发射极总周长不变的情况下,其发射结面积减少超过50%,集电结面积减少近70%,BVCBO也提高了近28%.经测试,器件的结漏电和直流增益等参数均符合设计要求. 相似文献
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基于器件结构特点和电学特性,研究了影响SiGe HBT(异质结双极晶体管)直流电流增益的主要因素,分析了不同的电流密度条件下,器件的物理参数、结构参数与集电极电流密度和中性基区复合电流的关系,建立了SiGe HBT集电极电流密度,空穴反注入电流密度、中性基区复合电流、SRH(Shockley-Read- Hall)复合电流密度、俄歇复合电流密度以及直流电流增益模型,对直流电流增益模型进行了模拟仿真,分析了器件物理、结构参数以及复合电流与直流电流增益的关系,得到了SiGe HBT直流电流增益特性的优化理论依据. 相似文献
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设计并制备了三种不同集电结结构的A lG aInP/G aA s异质结双极晶体管,计算给出了三种集电结能带结构。通过对三种HBT的直流特性测试表明,N pN型HBT因异质集电结的导带尖峰出现电子阻挡效应;N p iN型HBT集电结引入i-G aA s层能有效克服电子阻挡效应,同时还具有拐点电压Vknee小、开启电压Voffset小、击穿电压BVCEO大等优点,但由于i-G aA s层引入增加了基区电子扩散长度,使器件电流增益有所下降。 相似文献
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为了改善SiGe异质结双极型晶体管(HBT)的电学特性和频率特性,设计了一种新型的SGOI SiGe HBT。在发射区引入了双轴张应变Si层。多晶Si与应变Si双层组合的发射区有利于提高器件的注入效率。利用Silvaco TCAD软件建立了二维器件结构模型,模拟了器件的工艺流程,并对器件的电学特性和频率特性进行了仿真分析。结果表明,与传统的SiGe HBT相比,新型SGOI SiGe HBT的电流增益β、特征频率fT等参数得到明显改善,在基区Ge组分均匀分布的情况下,β提高了29倍,fT提高了39.9%。 相似文献
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A new analytical model for the base current of Si/SiGe/Si heterojunction bipolar transistors(HBTs) has been developed. This model includes the hole injection current from the base to the emitter, and the recombination components in the space charge region(SCR) and the neutral base. Distinctly different from other models, this model includes the following effects on each base current component by using the boundary condition of the excess minority carrier concentration at SCR boundaries: the first is the effect of the parasitic potential barrier which is formed at the Si/SiGe collector-base heterojunction due to the dopant outdlffusion from the SiGe base to the adjacent Si collector, and the second is the Ge composition grading effect. The effectiveness of this model is confirmed by comparing the calculated result with the measured plot of the base current vs. the collector-base bias voltage for the ungraded HBT. The decreasing base current with the increasing the collector-base reverse bias voltage is successfully explained by this model without assuming the short-lifetime region close to the SiGe/Si collector-base junction, where a complete absence of dislocations is confirmed by transmission electron microscopy (TEM)[1]. The recombination component in the neutral base region is shown to dominate other components even for HBTs with a thin base, due to the increased carrier storage in the vicinity of the parasitic potential barrier at collector-base heterojunction. 相似文献
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Hafizi M. Metzger R.A. Stanchina W.E. Rensch D.B. Jensen J.F. Hooper W.W. 《Electron Device Letters, IEEE》1992,13(3):140-142
The effects of base p-dopant diffusion at junction interfaces of InGaAs/InAlAs HBTs with thin base thicknesses and high base dopings are reported. It is shown that HBTs with compositionally graded emitter-based (E-B) junctions are very tolerant to base dopant outdiffusion into the E-B graded region. The RF performance is nearly unaffected by the diffusion, and the DC current gain and E-B junction breakdown voltages are improved with finite Be diffusion into the E-B graded region 相似文献
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We present a comparison of material quality and device performance of metamorphic InGaAs/InP heterojunction bipolar transistors
(HBTs) grown by molecular beam epitaxy (MBE) on GaAs substrates with two different types of buffer layers (direct InP and
graded InAlP buffers). The results show that the active layer of InP-MHBT has more than one order of magnitude more defects
than that of the InAlP-MHBT. The InAlP-MHBTs show excellent direct current (DC) performance. Low DC current gain and a high
base junction ideality factor from the InP-MHBT are possibly due to a large number of electrically active dislocations in
the HBT active layers, which is consistent with a large number of defects observed by cross-sectional transmission electron
microscopy (TEM) and rough surface morphology observed by atomic force microscopy (AFM). 相似文献
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This work quantifies neutral base recombination in UHV/CVD SiGe heterojunction bipolar transistors (HBTs) using calibrated two-dimensional (2-D) simulation. The simulated collector-base conductance through neutral base recombination (NBR) modulation is far below the experimentally observed values, and hence does not explain the measured output resistance degradation under forced-IB operation. In spite of the output resistance degradation, these UHV/CVD SiGe HBTs have approximately the same base current as the silicon control, and hence higher current gain. Based on the observation of the majority carrier concentration limited recombination in the CB junction depletion layer, as opposed to the minority carrier concentration limited recombination in the neutral base, local presence of traps in the CB junction depletion layer is suggested. This explains the measured CB conductance modulation and the related output resistance degradation without compromising the current gain. Numerical simulations using traps locally introduced into the CB junctions successfully reproduced the measured collector-base conductance from simulation without appreciable degradation in current gain 相似文献
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Meng-Wei Hsieh Yue-Ming Hsin Kung-Hao Liang Yi-Jen Chan Denny Tang 《Electron Devices, IEEE Transactions on》2006,53(6):1452-1458
This paper investigates the temperature dependence (from 77 to 300 K) of dc, ac, and power characteristics for n-p-n SiGe heterojunction bipolar transistors (HBTs) with and without selectively implanted collector (SIC). In SiGe HBTs without SIC, the valance band discontinuity at the base-collector heterojunction induces a parasitic conduction band barrier while biasing at saturation region and high current operation at cryogenic temperatures. This parasitic conduction band barrier significantly reduces the current gain and cutoff frequency. For transistors biased with fixed collector current, the measured output power, power-added efficiency, and linearity at 2.4 GHz decrease significantly with decreasing operation temperatures. The temperature dependence of output power characteristic is analyzed by Kirk effect, current gain, and cutoff frequency at different temperatures. The parasitic conduction band barrier in SiGe HBTs with SIC is negligible, and thus the device achieves better power performance at cryogenic temperatures compared with that in SiGe HBT without SIC. 相似文献