Electrical parameter extraction & modeling of SiGe HBT for HFapplications

Journal of Electrical and Control Engineering JECE

JECE Vol. 2 No. 2, 2012 PP. 27-34 C 2011-2012 World Academic Publishing

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Electrical Parameter Extraction & Modeling of Si1-xGex HBT for HF Applications

Pradeep Kumar#1, R. K. Chauhan*2 #1Department of ECE, Ideal Institute of Management & Technology, Ghaziabad, INDIA

*2Department of ECE, M.M.M. Engineering College, Gorakhpur, INDIA [email protected]; [email protected]

Abstract-SiGe technology is sincerely challenging III/V and II/VI technologies in the realm of high frequency electronics applications, for example optical fibre and mobile communications. In this paper a model of SiGe HBT with uniform impurity doping in the base for high frequency application is studied. The high frequency parameters are extracted with the help of simulated Z- and Y- parameters of two port equivalent circuits of the proposed SiGe HBT device and electrical parameters are calculated with the help of small-signal analysis of projected device. Later, the topics are also involved in instantaneous investigation of effect of Ge concentration on various electrical as well as HF parameters of this SiGe HBT. This method is validated by the examination of certain linear relations of device frequency behaviour as forecasted by the analogous theoretical analysis. Further, the precision of our method is validated by simulated S–parameter plots. The device characteristics of the proposed model are found much advanced to those of III-V semiconductor devices. These results have been also validated using a viable numerical device simulator ATLAS from Silvaco International.

Keywords-Silicon; SiGe；HBT; Ge Concentration; Small-signal Analysis; Intrinsic Parameters

I. INTRODUCTION

During the past several years, SiGe HBT technology has entered the global semiconductor electronics market. Now SiGe HBT technologies are being increasingly deployed in North America, Europe (such as dot5 project) for a wide variety of communications circuit applications such as cellular phones, in the microwave region and the semiconductor industry investing heavily to improve the performance of silicon devices for high frequency applications. The multibillion semiconductor industry is rapidly using devices/transistors working in several GHz regions and is pushing to demonstrate useful solid-state transistors, and resultant circuits built from them, capable of operating near the THz regime. There are two major driving forces for SiGe solid-state devices: 1) high frequency communications and radars and 2) various niche THz applications. Recent research has focused on expanding THz options from two-terminal devices (e.g., Schottky diodes) to three-terminal devices (transistors) for both application areas. In high-frequency communications and radars, higher bandwidth transistors are desirable in a number of applications. Optical fiber communications require active amplifiers in decision circuits, multiplexers, and phase-lock loops operating at 100-GHz clock frequency and above [1].

High current-gain and power-gain frequencies (fT and fmax) are also demanded in microwave, millimeter-wave, and

submillimeter wave transceiver designs, where progressive improvements in transistor bandwidth enable the evolution of communications and radars ICs operating to higher frequencies. In addition, faster transistors enable the wider band mixed-signal ICs (e.g., analog-to-digital converters, digital-to-analog converters, etc.) that improve the resolution of radars and communications systems [2]. Meanwhile, several hundred GHz applications are starting to expand from the initial niche markets of Earth, planetary, and space science to the larger commercial markets in biomedical imaging, non-metallic object detection, quality control, and secure communications.

For the meantime, application fields related to THz frequency range are expanded from the initial markets of planetary, earth and space science [3]–[6] to a bigger commercial markets in biomedical imaging, quality control, secure communications, and non-metallic object detection [7]. In present time, THz sensors are prepared from heterodyne semiconductors and novel direct detectors such as quantum-dot single-photon detectors and schottky diodes. THz sources are usually achieved through several optical techniques [8]. But, deficient existing oscillators and amplifiers made of active semiconductor transistors become a bottleneck. Furthermore, improved bandwidth in a transistor normally associates well with improved RF performance e.g. higher gain and lower noise. Thus THz transistors can significantly widen the design limitations of existing performance-constrained lower frequency (RF through millimeter-wave) circuits and systems [9][10]. An ample range of space electronics platforms (for instance analog, digital, and RF) are designed to operate at space and planetary ambient conditions which can be enabled by high-bandwidth bandgap-engineered transistors without bulky and power-hungry heating units [11].

The purpose of this work is to search physical issues of the device modelling of small-signal equivalent circuits for SiGe HBTs with uniform impurity doping in the base. During the last few years, various methods for parameter extraction and HBT high frequency small-signal modelling have been published and developed [12] – [16]. In 2002, Basaran and Berroth presented their model to extract the device parameters but it is not a simple and complete extraction method [17]. For ease of extraction process, a simple and accurate method is depicted in this proposed model. This device is simulated in ATLAS device simulator. In this process Y-, Z- and S-parameters are extracted directly by ATLAS. Then the electrical parameters are calculated with the help of above parameters and small-signal equivalent circuit analysis. In this work, a numerical simulation results are preferred instead of



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real measurement results for avoiding the interference from extrinsic parts in the calculation of small-signal parameters.

In this paper, we model the electrical as well as HF parameters and calculate the unity current-gain frequency and unity power-gain frequency for high speed applications of n-p-n SiGe HBT with uniform impurity doping in the base with the help of directly extracted Z-, Y-, and S-parameters. At the same time the effect of Ge concentration is investigated for above device parameters. With this impulse, we address small-signal HF modelling in the second section. In the third section, the simulation and calculated results are discussed. At last, we concluded with general protrusions and remarks in section-IV.

II. SMALL-SIGNAL HF MODELING

In this section, a simple, accurate, and novel extraction method is presented for discussing the transistor HF performance along with procedures to find out the parameters of SiGe HBT by means of small-signal π-topology equivalent circuits of this HBT with uniform impurity doping in the base. The algorithm is useful for extracting both intrinsic as well as extrinsic elements. The conventional methods derived from simple bias measurements work very sound when we determine formerly the extrinsic elements of the HBT. Through different procedures for example DC or optimization can be used for this strategy [18].

It is often very hard to accurately determine the values of parasitic elements of the HBT because the typical DC and cut-off techniques present poor performance for Silicon Germanium HBT devices. So an innovative procedure has been developed to circumvent this problem. In this technique only scattering (S)-parameters at different biases are measured. For fitting the measured S-parameters appropriately, linear models by way of π-topology have been experienced. For simplicity, we ignored emitter resistance, the collector resistance, together with the output resistance due to early effect [19].

Using ATLAS, the S-parameters which are obtained from AC analysis are simply converted into Y-, Z- or H-parameters. Various Power Gains for example MAG, MSG, as well as MAUG (are used for such analysis. Furthermore, a figure-of-merit that has been used extensively such characterization is maximum stable gain. At high frequencies these quantities are calculated from the measured small-signal scattering parameters due to simplicity of measurement [18].

Fig. 1 A small-signal Π equivalent circuit of an HBT device (a) contains intrinsic and extrinsic circuit elements. The intrinsic elements (b) can be determined from the admittance parameters of the device at a number of

different bias points

The maximum stable gain is calculated by y21 and y12 as [18],

21

12

MSGyy

(1)

And the maximum available gain is extracted as [18],

21 2

12

( 1)y

MAG k ky

(2)

Where k is ‘Rollett stability factor’ and extracted by this equation as [18],

11 22 12 21

12 21

2 Re( ) Re( ) Re( )k

y y y yy y

(3)

Mansion’s gain is obtained by the following equation as [18],

2

11 22 12 21

12 21

4[Re( ) Re( ) Re( ) Re( )]U

y yy y y y

(4)

The maximum available unilateral gain is calculated by this equation as [18],

2

11 22

21

4Re( )Re( )MAUG

yy y

(5)

We get the MAG when both input and output are concurrently conjugate matched. When k > 1, the device is unconditionally stable and MAG exists. It is obvious from Equations (4) and (5), if the device is unilateral (y12 = 0) then U equals to MAUG. The MAG equals to MSG and vice-versa when the device is unconditionally stable. Maximum frequency at which MSG becomes unity is frequently termed as fmax. As power gain with no impedance transformation is achieved by common-emitter microwave transistors. This is the reason why these transistors may comprise useful gain when inserted into a system with 50 Ω [18]. For this model, MSG is called a figure of merit. This device is unconditionally stable here.



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A. Frequency Response

In most HF and millimeter wave circuit applications, it is the frequency response of transistor that confines system performance. One of the imperative figures of merit in this context is the unity–gain cutoff frequency (fT), which is given as [20]

11

[ ( ) ]T eb Cb b c e

m

f C Cg

(6)

Where and are the EB and CB capacitances, gm is

the transconductance and , , are the base, emitter, and collector transit times, respectively. The transistor cut-off

frequency is thus a valuable metric for evaluating different

technologies. usually limits the maximum transistor in usual Si BJT’s,.

In the context of HF and millimetre-wave applications, the

unity power-gain frequency ( ), or maximum oscillation

frequency is a more relevant figure of merit because

depends not only on the intrinsic transistor performance ( ) but also the parasitics of the device, as [20]

max 8T

BCb

ff

C R

(7)

Where RB is the base resistance and CBC is the base-collector junction capacitance. Thus from Equation (7) it is clear that for the higher value of fmax, the value of base-collector junction capacitance and base resistance should be lower. So the cut-off frequency fT increases as transit time decreases which in turn affect the fmax.

B. Calculation of Intrinsic Parameters

The intrinsic and extrinsic parameters in Fig. 1 can be extracted by the following method: the base-emitter junction capacitance is calculated by the equation as follows [21],

11 12m mBE

i

I Y I YC

(8)

The base-collector junction capacitance is expressed by the equation as follows [21],

12mBC

i

I YC

(9)

The base-collector junction capacitance is expressed by the equation as follows [21],

22 12m mCE

i

I Y I YC

(10)

The base-collector junction capacitance is calculated by the equation as follows [21],

12

1

ReBCRY

(11)

The collector-emitter junction resistance is obtained by the equation as follows [21],

12 22

1

Re ReCERY Y

(12)

The collector-emitter junction resistance is expressed by the equation as follows [21],

11 12

1

Re ReBERY Y

(13)

In this method CBE are intrinsic junction capacitances and RBC, RCE and RBE are intrinsic junction resistances.

C. Calculation of Extrinsic Parameters

As the device dimension shrinks, the parameters RB and the parasitic capacitances start to measure the high frequency behaviour of the device and have to be taken into account in the equivalent circuit to improve the transistor model accuracy in the broad frequency range from Y parameters under the reverse-bias condition.

The extrinsic resistance is obtained by the equation as follows [18],

11 12BR Z Z (14) The base-collector junction capacitance can be measured as

[17],

12mBC

I YC

(15)

And the base-emitter junction capacitances can be measured as [17],

12 11mBE

I Y YC

(16)

III. RESULTS & DISCUSSION

On the basis of above model and method the values of many performance parameters such as electrical parameters and device high frequency parameters which include various intrinsic as well as extrinsic elements, current-gain (β), collector current, base resistance, junction capacitance, maximum oscillation frequency fmax, unity current-gain frequency (i.e. cut-off frequency) fT, are calculated for n-p-n SiGe HBT with uniform impurity doping in the base. Along with this effort, an investigation is also performed regarding the effect of Ge concentration on these parameters. For this purpose we find out the value of above parameters at different Ge concentrations. The HBT considered in this paper has the base width of 0.1µm. Average Ge concentration in this base region considered in our calculations is varied from 10%-28% as higher than this are not supported by present epitaxial technologies and beyond it the improvement associated with Ge seizes may be due to lattice constant mismatch [18].

ATLAS simulation of SiGe HBT is performed to prove precision. All important physical effects, such as impact ionization (II) is appropriately modeled and accounted for the simulation for obtaining admirable pact with characteristics. The impact ionization results in a strong improvement of collector-current. AC simulation needs apposite DC calibration



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which is an important prerequisite for it [18]. For this simulation, it is compulsory to take the complete device composition into account with the aim of considering the capacitance between substrate and collector (CCS) as well as capacitance between base and collector (CBC).

A. Determination Of Collector Current, Base Current And Gain Enhancement

A very important consequence of adding Ge into the base of a transistor is its effect on the collector current density (Jc). With Ge in the base, electron injection at the emitter base junction is made easier, and thus more charge can flow from the emitter to the collector with a resultant increase in Jc. Also, because of the Ge-induced band offset, there is a decrease in intrinsic carrier density in the base which also increases Jc [3]. As the emitter regions of both a Si BJT and a SiGe, HBT are essentially the same, implying an identical base current density (JB). The net result is that adding Ge increases the current gain of the transistor (β = JC/ JB) as in Figure 4. In testing, the maximum current-gain is found about 912 at 28% Ge content.

Fig. 2 Collector & Base currents of SiGe HBT

This plot indicates that the important DC consequence of adding Ge into the base, however, lies with the collector current density. Figure 2 shows the variation of IC & IB of SiGe HBT at various bias points. Figure 3 shows that effect of Germanium content on collector current and it is found that the IC increases as the concentration of Ge increases. We also investigated that the collector current is maximum at 28% Ge concentration and after this Ge concentration it does not follow the rule due to lattice constant mismatch.

The simulated SiGe HBT is shown in Figure 5.

B. Determination Of Intrinsic & Extrinsic Parameters

The intrinsic and extrinsic parameters are determined by Figure 1 and using Equations (8) to (16). Figure 1 is a small signal equivalent circuit of SiGe HBT device. The part (a) of it

shows the intrinsic as well as extrinsic element of HBT while the part (b) intrinsic part only. The intrinsic elements (b) can be determined from extracted Y- parameters of the device at a number of different bias points.

Fig. 3 Effect of germanium content on collector current

Fig. 4 Effect of Ge concentration over current-gain

Fig. 5 Simulated SiGe HBT Device with 0.1 µm Base width



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(1) Collector-Base junction Capacitance (CBC)

The collector–base capacitance is a junction capacitance. From Equation (6) and Equation (7) it is clear that the value of parasitic capacitance should be low for HF response. The collector-base junction capacitance can be calculated by imaginary part of Y12 as in Equation (9). The plot of CBC at is presented in Figure 6. The effect of germanium on the capacitance CBC can be visualized in Figure 7.

Fig. 6 Base-collector junction capacitance CBC

From this Figure it can be interpreted that on increasing the Ge concentrations the corresponding collector–base capacitance decreases which in turn increases the maximum oscillation frequency fmax [22]. The value of CBC is 2.76 ×10-

15.F at 0.28 Ge concentration.

Fig. 7 Effect of germanium on collector-base junction capacitance (CBC)

(2) Base Resistance (RB)

From Equation (7) it is clear that the base resistance should be low for higher fmax. It can be calculated by Z-parameters as in Equation (14). 】

Fig. 8 Effect of Ge concentration on base resistance RB

The Z-parameters are calculated from device simulator ATLAS. Figure 8 represents the effect of Ge concentration on base resistance. It is found that RB decreases as the concentration of Ge increases. 30.12 Ω RB has been obtained at 0.28 Ge concentration.

C. Determination of S- Parameters Plots

Figure 9 to Figure 12 show the simulated S-parameters plots for this device. Because of the intuitive relationship between coefficients S11 and S22 are conveniently on a smith chart, while S21 and S12 are representing the gain response and that’s why they are typically displayed on a polar plot. The S11 for a bipolar transistor always moves clockwise as frequency increases on the smith chart. The Figures 9 to 12 are simulated S11, S12, S21, and S22.

D. Determination of Maximum Oscillation Frequency (fmax) and Cut-Off Frequency (fT) for Proposed Device

The maximum oscillation frequency fmax is calculated by the method of extrapolation. This method requires the calculation of power-gain i.e. MSG. The power gain is calculated with the help of S- and Y-parameters of Si-Ge HBT device that are extracted from ATLAS. In this work MSG is calculated by Equation (1). The frequency vs. MSG plot is shown in Figure 13. As it is described above, the fmax is extracted at the point where MSG becomes 0 dB from MSG (in dB) versus log (frequency) plot. The extrapolated fmax is calculated 438 GHz at 0.28 Ge concentration from Figure 13. it is investigated that the maximum oscillation frequency fmax increases on increasing the Ge contents till 0.28 concentration beyond 28% it decreases due to lattice constant mismatch. At 0.28 Ge concentration a record 398 GHz corresponding fT is calculated. It is also investigated that the fT increases on increasing Ge concentration till 28% value of Ge contents. Figure 14 dipicts the variation of extrapolted fmax w.r.t. collector current. The Table 1 describes the overall summary of HF operation of SiGe HBT. It is found that this Si-Ge HBT device is operated at fmax and fT near half terahertz. This HBT in half Tera-Hertz frequencies encompass definite water absorption rates and imitate off metal. Apart from these areas,



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this device can infiltrate fog and fabrics [23]. Chemical detection, medicine, chemical spectroscopy, transportation, and national security in addition with weapon fields will also be enriched with this HBT. The study of dust & gas chemistry, stellar and galactic constituents as well as evolution cosmology

will be helped by these THz devices. This HBT in THz Radar will accommodate in investigating hidden universe and planet as well as space applications [18]. This data can be valuable for Dot 5 project.

Fig. 9 Simulated S11






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Fig. 13 Plot of frequency (HZ) vs. MSG (dB)

Fig. 14 Plot of collector current (IC) vs. extrapolated fmax (GHz)

TABLE 1 SUMMARY OF SiGe HBT OPERATION

Parameter Values for SiGe HBT with

uniform impurity doping in the base

fmax (Hz) 4.38 × 1011

fT (Hz) 3.98 × 1011

RB (Ohm) 30.12

CBC (F) 2.76 × 10-15

CCE (F) 1.96 × 10-15

β 912

IV. CONCLUSIONS

In this paper, a simple and accurate method of electrical parameter calculation and HF parameter extraction is presented for SiGe HBT with uniform impurity doping in the base. This is performed by simulated Z- and Y- parameters of proposed device and small signal equivalent circuit method. With the help of these parameters we calculated the intrinsic as well as extrinsic device parameters with higher precision. We found the fine value of base resistance and base-collector junction capacitance which are 30.12 Ω and 2.76 fF respectively. These two values are very helpful for figuring out the high frequency response of proposed device. The extrapolated unity power-gain frequency is calculated 438 GHz. The corresponding unity current-gain frequency is calculated 398 GHz. In our investigation we found that the device current-gain and collector current increases with increasing concentration of germanium. The β is calculated 912 at 28% Ge. While the base resistance and base-collector junction decreases with increasing values of Ge. The high frequency response of proposed model depicted near half tera hertz unity power-gain as well as unity current-gain frequencies. After 28% Ge concentration, these are not supported by present epitaxial technologies and beyond it the improvement associated with Ge seizes may be due to lattice constant mismatch. The proposed device with such frequency may be helpful in the realm of medicine, chemical spectroscopy and other space applications, and dot 5 project.

REFERENCES [1] M. J. W. Rodwell, M. Urteaga, T. Mathew, D. Scott, D. Mensa, Q. Lee, J.

Guthrie, Y. Betser, S.C. Martin, R. P. Smith, S. Jaganathan, S. Krishnan, S. I. Long, R. Pullela, B. Agarwal, U. Bhattacharya, L. Samoska, and M. Dahlstrom, “Submicron scaling of HBTs,” IEEE Trans. Electron Devices, vol. 48, no. 11, pp. 2606–2624, 2001.

[2] J. C. Candy, and G. C. Temes, Oversampling Delta-Sigma Data Converters. Piscataway, NJ, IEEE Press, 1992.

[3] R Mueller, “Terahertz radiation: applications and sources”, The Industrial Physicist, pp. 27–29, 2003.

[4] P. D. Coleman, and R. C. Becker, “Present state of the millimeter wave generation and technique art”, IEEE Trans. Microw. Theory Tech., vol. 7, no. 1, pp. 42–61, 1959.

[5] P. D. Coleman, “State of the art: Background and recent developments in millimeter and submillimeter waves”, IEEE Trans. Microw. Theory Tech., vol. MTT-11, no. 5, pp. 271–288. 1963.

[6] J. C. Wiltse, “History of millimeter and submillimeter waves”, IEEE Trans. Microw. Theory Tech., vol. MTT-32, no. 9, pp. 1118–1127, 1984.

[7] M. Mittleman, M. Gupta, R. Neelamani, R. G. Baraniuk, J. V.Rudd and M. Koch, “Recent advances in terahertz imaging”, Appl. Phys. B, Photophys. Laser Chem., vol. 68, no. 6, pp. 1085–1094, 1999.

[8] P. H. Siegel, “Terahertz technology”, IEEE Trans. Microw. Theory Tech., vol. 50, no. 3, pp. 910–928, 2002.

[9] J.S. Rieh, D. Greenberg, A. Stricker, and G. Freeman, “Scaling of SiGe heterojunction bipolar transistors”, in Proc. IEEE, 2005, vol. 93, no. 9, pp. 1522–1538.

[10] S. Weinreb, J. C. Bardin and H. Mani, “Design of cryogenic SiGe low noise amplifiers”, IEEE Trans. Microw. Theory Tech., vol. 55, no. 11, pp. 2306–2312, 2007.

[11] Jiahui Yuan, John D. Cressler, Ramkumar Krithivasan, Thrivikraman, Khater Tushar, H. Marwan, David C. Ahlgren, Alvin J. Joseph and Jae-Sung Rieh, “On the Performance Limits of Cryogenically Operated SiGe HBTs and Its Relation to Scaling for Terahertz Speeds”, IEEE Transactions on Electron Devices, VOL. 56, No. 5, 2009.

[12] Fu Jun, “Small-signal model parameter extraction for microwave SiGe HBTs based on Y- and Z-parameter characterization”, Journal of Semiconductors, Vol. 30, No. 8, 2009.

[13] J Gao, X Li and H Wang, “An approach to determine small signal model parameters for InP-based heterojunction bipolar transistors”, IEEE Trans Semicond Manuf, 19(1): 138, 2006.



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[14] L Degachi and F M Ghannouchi, “Systematic and rigorous extraction method of HBT small-signal model parameters”, IEEE Trans Microw Theory Tech, 54(2): 682, 2006.

[15] K Lee, K Choi and S H Kook, “Direct parameter extraction of SiGe HBTs for the VBIC bipolar compact model”, IEEE Trans Electron Devices, 52(3): 375, 2005.

[16] T R Yang, J M L Tsai and C L Ho, “SiGe HBT’s small-signal pi modeling”, IEEE Trans Microw Theory Tech, 55(7): 1417, 2007.

[17] Umut Basaran, and Manfred Berroth, “High frequency noise modeling of SiGe HBTs using a direct-parameter extraction method”, in Proceedings of IEEE, 2002.

[18] Pradeep Kumar and R. K. Chauhan, “Device parameter optimization osilicon germanium HBT for THz applications”, International Journal on Electrical Engineering and Informatics, Vol, 2, No. 4, 2010.

[19] “Device Simulation Software”, ATLAS User’s manual, SILVACO International, 2004.

[20] J. D. Cressler, “SiGe HBT technology: a new contender for Si-based RF and microwave circuit applications”, IEEE Trans. Microw Theory Tech., vol. 46, issue 5, pp. 572–589, 1998.

[21] J.M. Zamanillo, A. Tazon, A. Mediavilla and C. Navarro, “Simple Algorithm Extracts SiGe HBT Parameters”, Microwaves & RF, pp. 48-57, 1999.

[22] Ankit Kashyap and R. K. Chauhan. “Effect of the Ge profile design on the performance of an n-p-n SiGe HBT-based analog circuit”, Microelectronics journal, MEJ: 2554, 2008.

[23] Frank Chang. “Terahertz CMOS SoC for Imaging/Communication Systems” tech. ppt, UCLA, High-Speed Electronics Laboratory.

Pradeep Kumar was born in Allahabad, India in 1985. He received his B.Tech. degree in Electronics & Communication Engineering from KCNIT Banda in 2006 and M. Tech degree in Digital Systems from Madan Mohan Malviya Engineering College, Gorakhpur, India. He initially joined VINCENTIT Hyderabad in 2006 and thereafter worked as a lecturer in Dr. K.N.M.I.E.T. Modinagar, Ghaziabad between 2007 and 2008. He is currently working as Assistant Professor in the Deptt. Of Electronics & Communication Engineering at Ideal Institute of Management and Technology

Ghaziabad India. His research interests include characterization & modeling of SiGe HBT based circuits, THz & millimeter-wave circuit application and mixed signal processing. E-mail: [email protected] Ph: +91-9540642891 Department of ECE, Ideal Institute of Management and Technology Ghaziabad, INDIA.

R. K. Chauhan was born in Dehradoon, India in 1967. He received the B.Tech. degree in Electronics & Communication Engineering, from G.B.P.U.A.T - Pantnagar, in 1989 and M.E. in Control & Instrumentation, from MNNIT-Allahabad in 1993 and Ph.D in Electronics Engineering, from IT-BHU, Varanasi, INDIA in 2002. He joined the department of ECE, Madan Mohan Malviya Engineering College, Gorakhpur, India as a lecturer, in 1993, as an Assistant Professor since 2002 and thereafter as an Associate Professor since Jan, 2006 to till date in

the same institute. He also worked as a Professor in Department of ECE, Faculty of Technology, Addis Ababa University, Ethiopia between 2003 to 2005. He is reviewer of Microelectronics Journal, CSP etc. His research interests include device modeling and simulation of MOS, CMOS and HBT based circuits. He was selected as one of top 100 Engineers of 2010 by International Biographical Centre, Cambridge, England. E-mail: [email protected] Ph: +91-9235500556 Department of ECE, Madan Mohan Malviya Engineering College, Gorakhpur-273010, India.

Electrical parameter extraction & modeling of SiGe HBT for HFapplications

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