共查询到20条相似文献,搜索用时 6 毫秒
1.
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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用解析的方法模拟了T=300K和77K时,fT和fmax与集电极电流密度Jc的关系,在大电流下考虑了异质结势垒效应的影响。模拟结果和用数值方法以及实验所得到的结果一致。同时,还建立了与之相应的Si/SiGeeb异质结和SiGe/Sibc异质结电容模型。 相似文献
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Bary L. Borgarino M. Plana R. Parra T. Kovacic S.J. Lafontaine H. Graffeuil J. 《Electron Devices, IEEE Transactions on》2001,48(4):767-773
An experimental setup, based on current/voltage conversion through transimpedance amplifiers (TAs), has been implemented for the direct full low-frequency noise (LFN) characterization of Si/SiGe heterojunction bipolar transistors (HBTs) in terms of base and collector short-circuit current noise sources. This setup performs a full characterization, as it measures simultaneously the two noise current sources and their correlation, thanks to an original technique based on the specific properties of a specially designed buffer amplifier using a low-noise common-base bipolar transistor (CB BJT). By means of translation formulae, the obtained measurements are compared with those carried out with a multi-impedance technique. They show a good agreement both for the noise sources spectral densities and for their correlation. The TA-based setup provides enhanced capabilities in terms of measurement speed and remote control potentialities 相似文献
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Sheng-Yi Huang Kun-Ming Chen Guo-Wei Huang Hua-Chong Tseng Tsun-Lai Hsu Chun-Yen Chang Tiao-Yuan Huang 《Electron Device Letters, IEEE》2004,25(6):393-395
This letter investigates hot-carrier (HC) effects on the power characteristics of Si-SiGe HBTs using load-pull measurements. We found that the output power, power gain, and linearity of Si-SiGe HBTs are degraded after HC stress. Under constant base-current measurement, the HC-induced power performance degradation is found to be much worse than that under constant collector-current measurement. The HC effects on the cutoff frequency, nonlinearity terms of base-current and collector-current, and third-order intermodulation (IM3) cancellation effect have been analyzed to explain the experimental observations. 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
7.
The quality of MBE-grown Si/SiGe heterojunction bipolar transistors (HBTs) was improved by inserting a well-defined undoped SiGe layer between the neutral base and the collector. The DC characteristics and the long-term stability of these non-selfaligned devices proved to be excellent, and the transit frequency reached 33 GHz (V/sub CB/=1 V). Those features are essential preconditions for future application in high-speed ICs.<> 相似文献
8.
We present a physically based comparison of the current spectral densities in a SiGe heterojunction bipolar transistors (HBT) and a Si bipolar junction transistor (BJT) of identical geometry and doping levels, based on the direct evaluation of emitter, base and collector current fluctuations. An ensemble Monte Carlo (EMC) simulator self-consistently coupled with a 2D Poisson solver has been employed for the calculations. In the studied bias range, the largest reduction of the RF current noise values in the HBT as compared with the BJT derives from the spectral density of base current fluctuations, SJB, and from the spectra of the cross-correlation between emitter and base current fluctuations, SJBJE. This is due to the fact that the base current in the HBT is strongly reduced as a consequence of the lower gap of the SiGe base. At low injection, the collector spectral density SJC exhibits a typical shot noise response while SJB is governed by thermal noise. At high injection, the presence of hot carriers in the base–collector junction (which are less important in the HBT than in the BJT due to the SiGe/Si hetero-interface), the high carrier concentration in the base and the base push-out provokes the deviation of SJC from the pure shot behavior. Under these conditions, the SJB term can be neglected in the total noise analysis of the HBT for lower values of JC, than in the BJT due to the Ge content benefits. 相似文献
9.
Krithivasan R. Yuan Lu Cressler J.D. Jae-Sung Rieh Khater M.H. Ahlgren D. Freeman G. 《Electron Device Letters, IEEE》2006,27(7):567-569
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). 相似文献
10.
Dongyue Jin Wanrong Zhang Hongyun Xie Liang Chen Pei Shen Ning Hu 《Microelectronics Reliability》2009,49(4):382-386
The two-dimensional temperature profile of a power SiGe HBT with traditional uniform emitter finger spacing is calculated, which shows that there is a higher temperature in the central region of the device. With the aid of the theoretical analysis, an optimized structure of the HBT with non-uniform emitter finger spacing is presented. The peak temperature is lowered by 23.82 K, and the thermal resistance is also improved by 15.09% compared with that of the uniform one. The improvements above are ascribed to the increasing the spacing between fingers, and hence suppressing the heat flow from adjacent fingers to the center finger. Based on the analytical results, two types of HBTs with uniform emitter finger spacing and non-uniform emitter finger spacing are fabricated and their temperature profiles and thermal resistance are measured. The measured results agree well with the calculated results, verifying the accuracy of the calculations. For the HBT with non-uniform emitter finger spacing, the peak temperature and the thermal resistance are improved markedly over a wide biasing range compared with that of the uniform one. Therefore, both the calculated results and the experimental results verify that the optimized structure of power HBT with non-uniform emitter finger spacing is superior to the uniform emitter spacing structure for enhancing the thermal stability of power devices over a wide biasing range. 相似文献
11.
《Solid-state electronics》2004,48(10-11):2001-2006
High power bipolar transistors often have multiple emitters, to achieve high currents, and efficient use of the whole emitter area. The emitters experience high current densities and are self-heated above the ambient temperature, leading to concerns about thermal run-away and damage to the device. Here we use a multi-emitter SiGe HBT, with multiple emitter contacts, to examine the temperature distribution in the emitters in such devices. We have measured the temperature increase in different emitters by biasing one emitter at a time and using the other base–emitter junctions as thermometers. We show that use of a selectively implanted collector does not alter the temperature increase or thermal coupling between the emitters. 相似文献
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RF linearity characteristics of SiGe HBTs 总被引:1,自引:0,他引:1
Guofu Niu Qingqing Liang Cressler J.D. Webster C.S. Harame D.L. 《Microwave Theory and Techniques》2001,49(9):1558-1565
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 Ic an optimum Vce exists for a maximum third-order intercept point (IIP3). The IIP3 is limited by the avalanche multiplication nonlinearity at low Ic, and limited by the CCB nonlinearity at high Ic. The decrease of the avalanche multiplication rate at high Ic 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 Ic and Vce. 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 相似文献
15.
Zhenqiang Ma Ningyue Jiang 《Electron Devices, IEEE Transactions on》2005,52(2):248-255
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. 相似文献
16.
High-speed scaled-down self-aligned SEG SiGe HBTs 总被引:1,自引:0,他引:1
Washio K. Ohue E. Hayami R. Kodama A. Shimamoto H. Miura M. Oda K. Suzumura I. Tominari T. Hashimoto T. 《Electron Devices, IEEE Transactions on》2003,50(12):2417-2424
A scaled-down self-aligned selective-epitaxial-growth (SEG) SiGe HBT, structurally optimized for an emitter scaled down toward 100 nm, was developed. This SiGe HBT features a funnel-shaped emitter electrode and a narrow separation between the emitter and base electrodes. The first feature is effective for suppressing the increase of the emitter resistance, while the second one reduces the base resistance of the scaled-down emitter. The good current-voltage performance - a current gain of 500 for the SiGe HBT with an emitter area of 0.11 /spl times/ 0.34 /spl mu/m and V/sub BE/ standard deviation of less than 0.8 mV for emitter width down to about 0.13 /spl mu/m - demonstrates the applicability of this SiGe HBT with a narrow emitter. This SiGe HBT demonstrated high-speed operation: an emitter-coupled logic (ECL) gate delay of 4.8 ps and a maximum operating frequency of 81 GHz for a static frequency divider. 相似文献
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Linearity and power characteristics of SiGe HBTs at high temperatures for RF applications 总被引:2,自引:0,他引:2
Kun-Ming Chen An-Sam Peng Guo-Wei Huang Han-Yu Chen Sheng-Yi Huang Chun-Yen Chang Hua-Chou Tseng Tsun-Lai Hsu Liang V. 《Electron Devices, IEEE Transactions on》2005,52(7):1452-1458
In this paper, the power gain, power-added efficiency (PAE) and linearity of power SiGe heterojunction-bipolar transistors at various temperatures have been presented. The power characteristics were measured using a two-tone load-pull system. For transistors biased with fixed base voltage, the small-signal power gain and PAE of the devices increase with increasing temperature at low base voltages, while they decrease at high base voltages. Besides, the linearity is improved at high temperature for all voltage biases. However, for devices with fixed collector current, the small-signal power gain, PAE, and linearity are nearly unchanged with temperature. The temperature dependence of power and linearity characteristics can be understood by analyzing the cutoff frequency, the collector current, Kirk effect and nonlinearities of transconductance at different temperatures. 相似文献
18.
A current gain cutoff frequency fT of 508 GHz is reported for a SiGe heterojunction bipolar transistor (HBT) operating at 40 K. This 63% increase over the 311 GHz value measured at room temperature results from the overall decrease of the transit and charging times. Two HBTs are compared to highlight the importance of the topology of the HBT to reach maximum performances. 相似文献
19.
Slotboom J.W. Streutker G. Pruijmboom A. Gravesteijn D.J. 《Electron Device Letters, IEEE》1991,12(9):486-488
Parasitic energy barriers can easily be introduced during processing. Measurements and calculations of experimental n-p-n HBTs (heterojunction bipolar transistors) are presented, showing that a parasitic conduction-band barrier at the base-collector junction reduces the collector current and the cutoff frequency. A simple analytical model explains the f T degradation, caused by the reduction of the collector current and a pileup of minority carriers in the base. With the model the effective height and width of the barrier can also be derived from the measured collector current enhancement factor I C(SiGe)/I C(Si) 相似文献
20.
SiGe/Si异质结器件 总被引:1,自引:0,他引:1
本文综述了国际上SiGe/Si异质结器件的发展状况,分析了该器件的结构要理,特点,优越性及制造技术,阐述了该器件的广阔应用和对微电子将产的重大影响。 相似文献