1. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
Design of an improved transistor performance for RF application using
Bipole3 Simulator
Mohamed Abdultawab Abdulla
Department of Electronics and Communication, Faculty Of Engineering, Aden University
Abstract
This paper presents a bipolar junction transistor simulation working at radio frequency (RF)
applications, using the device simulator Bipole3. First, the simulator was calibrated with physical
parameters, after that calibration was made for data measurement, then the transistor was
simulated.
A key figure of merit of a transistor is the transit frequency fT. However, this improvement
comes at the expense of increased base resistance Rb and reduced early voltage VA (linearity), both
of which are detrimental to RF performance. The higher base doping concentration provides
advantages in both higher early voltage, due to less modulation of the space region into the neutral
base, and a low noise figure 1/f , due to the low Rb, and high current gain (β), which are translated
into performance advantages for RF applications [4].
Key words: SiGe HBT, RF Transistor, Bipole3 Simulator
1-Introduction
The addition of germanium (Ge) in the base of the BJT Transistor provides a SiGe
Heterojunction Bipolar Transistor (HBT) device with simultaneously high fT and cut off frequency
(fmax), which improves the gain and efficiency over conventional Si BJTs. For the same amount of
operating current, SiGe HBT has a higher gain, lower (RF) noise figure (NF), and low 1/f noise.
The higher raw speed can be traded for lower power consumption as well [5].
The main Bipole3 program performs a simulation of the HBT in a plane vertical to the
semiconductor surface using the complete impurity profile data; this includes vertical profiles in
'slices' through the active emitter to substrate, and through the collector sinker, extrinsic base,
isolation regions ( see appendex).
The Bipole3 bipolar device simulation program is based on the Variable Boundary Regional
Approximation (VBRA). In the vertical 'x' direction (emitter - base - collector), the device is
divided into 5 regions, as shown in Figure (1) [3].
Fig. (1). Impurity profile with neutral and space charge regions marked 1 - neutral emitter, 2 - emitter-base
space charge layer, 3 - neutral base, 4 -base-collector space charge layer and 5 - neutral collector.
Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December 2011
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2. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
The vertical simulation is performed for a range of Vbe bias values and specified Vcb bias. The
results are then used in a one - dimension horizontal plane simulation in the active base region to
yield terminal characteristics with a high degree of accuracy [2].
2- Simulation
Experimental Processing Method
The starting point for a new design is an existing HBT structure with a known impurity profile
and mask dimensions. We take a design example device (SiGeoldo) with a peak fT of 43GHz with
emitter dimensions: width (elem) of 0.5µm, length 10µm. The junction depths are: emitter-base
0.019µm; and base-collector 0.076µm. A selectively implanted collector (SIC) is used. The Ge
fraction is constant at 0.05 (5%) throughout the base region [6].
The characteristics of most importance are usually breakdown voltage, current gain, maximum
fT, maximum fmaxosc. We start by modifying the value of elem and the corresponding mask layout
parameters. The elem is reduced to 0.25µm to determine the impurity profile required for the
improved electrical characteristics, specifically a peak f T of 70GHz. All other mask dimensions are
reduced by comparable widths and maintaining comparable current gain. The effect of decreasing
the junction depths is best done gradually. Hydrodynamic Model (HDM) effects should be included
by the use of the IHDM parameter. There is a slight HDM effect, the magnitude of the effect
depends on the vertical thicknesses of the various regions.
The next process is to analyse the resulting data. Based on the results obtained, our input
file was made, and a SiGe HBT was simulated [1].
INPUT FILE: Mohamed A. Tawab.BIP
BIPSIM Inc & UNIVERSITY OF WATERLOO
QUASI 3D BIPOLAR DEVICE SIMULATION AND MODEL GENERATION PROGRAM
BIPOLE3 VERSION V.5.1U (C) D.J. Roulston
THIS BIPOLE3 COPY IS FOR INDUSTRIAL USE AUTHORIZED BY
Bipsim Inc., Ontario, Canada NO COPYING IS PERMITTED
THE NON-DEFAULT VALUED PARAMETERS ARE:
SiGe base heterojunction layer:
ISIGE = SiGe HBT flag to set Ge (x) options
XGE= Ge fraction at base-emitter junction
XGEP= Ge fraction at base-collector junction
XJ1G= Depth of emitter-base junction
XJ2G= Depth of base-collector junction
XJ1G
XRAM1 XJ2G
XRAM2
.420E-05 .500E-06 .600E-05 .500E-06
IGAP (7) is used for the SiGe HBT option. If the base germanium fraction XGE is specified with
IGAP = 7, the band-gap reduction in the base is given by: E(reduction) = 0.75 * XGE (Ev), with
further band-gap reduction due to heavy doping, as described by the formula of Slotboom.
ISIGE (1) The Ge fraction is zero up to a depth of XJ1G - XRAM1, then it increases linearly to
a value of XGE at a depth of XJ1G and linearly up to a value XGEP at the XJ2G. A ramp down
XRAM2 starting at XJ2G is used if XGE, XGEP, XJ1G, XJ2G, are specified. These four
quantities are defined with the above values of ISIGE.
The Ge (x) profile, may be defined in several different ways according to the values of the input
parameters IGAP, and ISIGE used. We have used IGAP =7, ISIGE =1 with the Ge (x) distribution
parameters.
Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December 2011
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3. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
Germanium Fraction vs. Depth
0.055
0.05
M0hamed Ge Fraction
0.04
0.035
0.03
0.025
0.02
Ge fraction
0.045
0.015
0.01
0.005
0
0.035
0.04
0.045
0.05
microns
0.055
0.06
0.065
Fig (2). Ge fraction vs depth junctions
Mask Data
Figure (3) Discrete transistor mask definitions
ELEM
B
ESB
ECB
BPB
ELPB
7.00E-05 2.00E-03 2.00E-05 2.50E-05 2.20E-03 1.65E-04
ELEM = (INPUT) Emitter stripe width.
B = The length of the base contact parallel to the emitter.
ESB = Space between base contact and emitter diffusion.
ECB = Width of base contact.
BPB = (INPUT) Length of base region diffusion.
ELPB = (INPUT) Width of base diffusion.
Impurity Profile:
Figure (4) Impurity profile for Impur = 1
The impurity profile is defined using Impur = 1 which requires input values for the donor and
acceptor distributions. Impur = (0) User specified junction depths are used to obtain the
characteristic lengths of the two Gaussian functions XE1 and XB1. The quasi gaussian functions
may be used; this enables excellent fits to any profiles measured or obtained from a process
simulator. A simple representation for the distribution is defined by Fig. (4).
Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December 2011
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4. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
NE1 = (INPUT) Emitter diffusion surface concentration.
NB1 = (INPUT) Base diffusion surface concentration.
NEPI = (INPUT) Epitaxial layer doping level.
XE1 = Computed value of Gaussian characteristic length for emitter diffusion (Impure = 0).
XB1 = Computed value of Gaussian characteristic length for base diffusion.
NXE1 = (INPUT) Integer exponent of first emitter 'gaussian'.
NXB1 = (INPUT) Integer exponent of first base 'gaussian'.
XEND = (INPUT) Total epitaxial layer thickness. This is the depth at which the simulation is
stopped. Zero voltage drop is assumed for depths greater than XEND. XEND can therefore be
often taken to be the epitaxial layer to N+ substrate interface.
NE1
NB1
NEPI
XE1
XB1 XEND NXE1 NXB1
5E+20 2E+19 1E+17 3E-06 5E-06 9E-05
4.0
4.0
Implanted collector profile
A selective implanted collector (SIG) is incorporated using the ISIC = 1, with Impur = 1.
XE3 = Characteristic length of third donor Gaussian.
NXE3 = Exponent of third donor profile.
The dose, PHI, the RANGE, and the value of SIGMA are related directly to the input
parameters (peak doping, position, characteristic length).
5.0E+18 AT x = 2.0E-05 FOR
XE3
NXE3
PHI
RANGE
SIG
1.0E-05
2.0
8.9E+13
2.0E-05
7.1E-06
Profile integration
XEPI= Computed value of epitaxial layer thickness.
XJ1 = Depth of emitter-base junction.
XJ2 = Depth of base-collector junction.
TEPI = Epi. layer thickness measured from substrate to surface.
XSUB = Characteristic length of Gaussian back diffusion.
NSUB = Exponent of quasi Gaussian in back diffusion.
NSUBO = N+ substrate or buried layer peak doping level.
XEPI
XJ1
XJ2
TEPI
XSUB
NSUBO
6.68E-06 4.18E-06 6.61E-06 5.00E-05 5.00E-06 1.00E+19
Collector sinker and buried layer
NCOL = Surface donor concentration.
XNCOL = Diffusion characteristic length.
XNCOLP = Position of peak of NCOL profile.
NXNCOL = Gaussian exponent.
NCOL XNCOL NXNCOL Rsink Rsink/sq Rsink*cm**2
1E+20 5.0E-5
2.0
4.33E-1 1.78E+1
4.76E-8
Recombination Parameters:
The recombination lifetime data is specified by the following input parameters: ITAUE,
ITAUB and ITAUC set to '1' for doping dependent recombination in each of the three regions into
which the case of lifetimes TAUE (Reference lifetime of carriers in emitter region), TAUB
(Reference lifetime of carriers in base), TAUC (Reference Lifetime of carriers in collector) are
used as the reference lifetimes (TAUR).
The depletion layer regions are characterized independently by recombination lifetimes
TAUDE (Recombination lifetime in e-b (space charge layer) s.c.l. for the e-b junction) and
TAUDC (for the c-b junction), using the excess charge in the space charge layer by integration.
ITAUE ITAUB ITAUC TAUDE TAUE TAUB TAUC
1
1
0
2E-07
1E-08 1E-06 1E-06
Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December 2011
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5. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
3- Results and Discussion
We make modifications to the original file, after the calibration procedure was done to the
measuring data and the physical parameters.
To obtain realistic mask layouts, we altered some mask data (bpc, elen; elpb) sof1f, and
(elns, elps) sof2f. We also adjusted the impurity profile values xe1and xb1 to obtain the required
junction depths.
We ran the Bip2neut extension Module to obtain the correct values for felat and fqlat. We
ran the Non Equilibrium Transport simulation, using ION (for ionization integral) = 20 separately,
to obtain BVceo values 1.10 V for sof1f and 1.30 V for sof2f. For HBTs with peak fT values in
excess of around 30GHz , it is essential to use a Non Equilibrium Transport model for correct
simulation of avalanche multiplication.
Net Doping vs. Depth
1e+21
SOF2F Net Doping
SOF1F Net Doping
1e+20
cm - 3
1e+19
1e+18
1e+17
1e+16
0
0.1
0.2
0.3
0.4
microns
0.5
0.6
0.7
GHz
Fig. (5) Impurity profile
The two impurity profiles and fT vs IC plots are shown in Figs (5, 6).
100
90
80
70
60
50
40
30
20
10
0
Ft vs. Ic
SOF2F Ft
SOF1F Ft
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1
Amp
Fig. (6) fT vs IC
As the SIC implant dose increases, BVceo decreases. At the same time the CB capacitance
rises; this has a deleterious effect on fmaxosc, specially at medium and low currents. The higher dose
enables higher operating current densities, thus improving the fmaxosc versus IC curves, as shown in
Fig. (7).
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6. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
Fmax oscillation vs. Ic
140
SOF2F Fmax oscillation
SOF1F Fmax oscillation
120
100
GHz
80
60
40
20
0
0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1
Amp
Fig. (7) fmaxosc vs IC
Figure 8 shows the high values of current gain; the reason for this high values of β is the deep
emitter and poly emitter. This may not be realistic in a real device with an implanted base.
Industrial emitters for very high fT HBTs tend to be much shallower. The use of quite high Ge
values in the base gives a rise to very high current gains (β vs Ic). It is possible that recombination
parameters in the emitter need to be adjusted to bring these values down to realistic values. In this
case, surface recombination will reduce the current gain. Incidencially, the f T is not influenced
much by the base doping level. Also the fmax increases due to increased base doping, but decreases
due to increased capacitance Cjc so overall fmax does not change much, with base doping increased.
Beta AC vs. Ic
1e+06
SOF2F Beta AC
SOF1F Beta AC
B eta A c
100000
10000
1000
1e-05
0.0001
0.001
0.01
0.1
Amp
Figure (8) current gain β vs Ic
We have modified our files with 2 new input data sof1n and sof2n to get reduced current gains.
The modifications included:
a) setting XGE = XGEP = 0.1
b) increasing the base doping NB1 with NXB1 = 6. (the emitter doping NE1 was correspondingly
increased to keep a reasonable emitter impurity profile with NXB1 = 6. This requires several
iterations to keep the junction depths constant),
c) decreasing the emitter recombination lifetime TAUE. In practice. This is a process dependent
and, therefore, is not predictable as surface recombination which we did not alter, and
d) adjusting the values of XE1, XB1 to maintain the original junction depths and neutral base
widths, using small changes ensure that conditions remain within realistic bounds.
Figure (9) shows the impurity profiles for the 2 new transistor input data
Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December 2011
628

7. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
Net Doping vs. Depth
1e+21
SOF2N Net Doping
SOF1N Net Doping
1e+20
cm -3
1e+19
1e+18
1e+17
1e+16
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
microns
Fig. (9) Impurity profiles for 2n and 1n data
Figures (10 and 11) show the fT and fmax versus IC plots for the new transistors
Ft vs. Ic
SOF2N Ft
SOF1N Ft
100
G Hz
80
60
40
20
0
0
0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18
Amp
Fig. (10) fT vs IC
Fmax oscillation vs. Ic
SOF2N Fmax oscillation
SOF1N Fmax oscillation
120
100
GHz
80
60
40
20
0
0
0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18
Amp
Fig. (11). fmax vs IC
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8. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
The current gain plots are shown in Figure (12)
Beta AC vs. Ic
300
SOF2N Beta AC
SOF1N Beta AC
250
B eta A c
200
150
100
50
0
1e-06
1e-05
0.0001
0.001
Amp
0.01
0.1
1
Fig. (12). Current gain versus IC
In the vertical analysis the values of the parameters are determined using VCIN = 1
JN
βE
VBE τRE
τEM τ scl FTOT WB
JP
βtot M
τ QBE
τB
τRC
FTMAX VCB
The analysis starts with the generation of the impurity profile. This may be obtained from
quasi-Gaussian analytic functions (the sum of two quasi-gaussians for the emitter and another two
for the base profile).
The values of the quasi gaussian characteristic lengths used are shown in Table (1).
Table (1): The values of the quasi gaussian characteristic length used
Device
Xe1
Xb1
Sof1f
.025E-04 .041E-04
Sof2f .0435E-04 .073E-04
Sof1n .027E-04 .040E-04
Sof2n .047E-04 .084E-04
The new junction depths XG1J are 0.3E-5 and 0.6E-5µm (e-b) and XG2J are 0.5E-5 and 0.1E4µm (b-c), respectively.
Lateral Analysis in the Neutral Base Region ('y' Direction) for majority carrier current was
done using the results from vertical analysis. Note that the region boundaries, the current densities,
Vbe values, etc. are all a function of both 'x' and 'y'.
The values of the parameters from the horizontal simulation are taken as a function of
collector current: Emitter Width = 0.2E-4CM, VCB = -0.1E1V
IC
VBE βDC fT
rB(DC)
IB
CROWD JCMAX
IC
GM βAC fmosc
rB(AC)
CEBT CCBT
CDiff
The Bipole3 program automatically selects the collector current range (or V be range) based on
the impurity profile data. The result of one integration along the width 'L' of the emitter is the total
collector current, base current and the corresponding current gain, total charge (in all regions), base
resistance voltage drop, etc. The values of rb (dc), rb , fT allow to calculate the noise parameters
NFmin.
The value of fT is extracted from the numerical solution using a low frequency small signal
method to determine all the delay times. It thus corresponds to measured values extracted from
current gain plots at frequencies slightly above the beta cut-off frequency, where the slope is 630
Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December 2011

9. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
20dB/decade. The maximum oscillation frequency fmaxosc is calculated from the classic formula by
using the extracted small signal values of fT, rbb, Cjc.
Table (2) shows the summary of terminal characteristics using the results from vertical and
lateral analysis for VCB = 1.
Table (2): Asummary of terminal characteristics
VBE
β
RB
FT
FMOSC
Sof1f
IC
Low Current 6.38E-05 6.00E-01 1.67E+ 8.48E+ 4.56E+ 6.59E+
05
01
09
09
GAIN MAX
1.20E-04 6.18E-01 1.71E+ 8.20E+ 8.31E+ 9.04E+
05
01
09
09
FT MAX
1.19E-02 7.98E-01 1.17E+ 5.10E+ 9.86E+ 3.94E+
05
01
10
10
Sof2f
IC
VBE
β
Low Current 2.74E-05 6.00E-01 3.25E+
04
GAIN MAX
2.62E-03 7.25E-01 4.62E+
04
FT MAX
1.36E-02 7.92E-01 4.28E+
04
β
8.29E+
01
1.35E+
02
1.03E+
02
β
1.63E+
02
2.75E+
02
1.55E-02 8.68E-01 2.04E+
02
Sof1n
IC
VBE
1.07E-06 6.00ELow
Current
01
GAIN MAX 1.13E-04 7.21E01
FT MAX
4.41E-02 1.03E+
00
Sof2n
IC
VBE
Low
2.37E-06 6.00E-01
Current
GAIN MAX 2.33E-04 7.21E-01
FT MAX
RB
1.14E+
01
1.05E+
01
9.11E+
00
RB
1.88E+
01
1.86E+
01
1.74E+
01
RB
1.45E+
01
1.33E+
01
1.02E+
01
FT
1.40E+
09
5.40E+
10
8.15E+
10
FT
5.91E+
07
5.55E+
09
1.05E+
11
FT
1.29E+
08
9.34E+
09
7.09E+
10
FMOSC
1.51E+
10
9.85E+
10
1.31E+
11
FMOSC
1.58E+
09
1.54E+
10
6.91E+
10
FMOSC
4.11E+
09
3.64E+
10
1.16E+
11
4- Conclusions
1. Bipole3 is an extremely powerful TCAD tool for evolving a new improved SiGe HBT design.
2. SiGe HBT device is simulated, and the SiGe layers are keept below the critical layer
thickness of SiGe layer.
3. The doping and Ge profiles were optimized to obtain high fT and fmaxosc device.
4. Based on the optimized input parameters, and the results from the horizontal and vertical
analysis, SiGe transistorized structures are being projected with streamlined parameters (β, fТ,
fmax,BVCB0 and BVCЕ0).
Acknowledgement
I would like to give my greatest thanks and appreciation to Prof. Deived Roulston, who who
provides me with a lot of useful comments and suggestions, guidance, encouragement, technical
discussions and technical contribution, calibration, and simulation during the experimental
processing. I also give my thanks to Prof. Dr. Geno Dimitrov, Prof. Dr. Jasem AL-Samaraee and
Prof. Dr. Zein AL-Sakaff for their kind assistance.
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10. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
Appendex (1) Bipole3 technical overview [1]
Bipole3 is a semiconductor device numerical simulation package. It has built-in structure
definitions (mask templates) and impurity profiles for vertical npn and pnp bipolar junction
transistors (BJTs), including SiGe HBTs and also MOSFETs. The impurity profiles may be
supplied as either analytic (quasi Gaussian) functions or as tabular data obtained from process
simulators or from measurements. For SiGe HBTs, a wide range of analytic Ge (x) profiles may
be described as input; alternatively the Ge (x) profile may be supplied as tabular data. Because of
its fast execution speed, Bipole3 is ideal for engineering design. This includes
optimization/sensitivity studies in which input variables such as impurity profile and/or mask
dimensions, can be varied thousands of times in a few hours.
Bipole3 contains essentially the same physical models (e.g. band-gap narrowing, mobility versus
doping, carrier recombination versus doping) and performs full numerical simulation in two
coupled one- dimensional solutions plus a two dimensional numerical solution for sidewall regions.
The results are generally close to those contained with full 2D simulators but in a time which is
about one hundred times shorter, including SPICE parameter extraction.
The 2D current injection region from the emitter sidewalls is solved optionally, using the
BIP2NEUT Extension Module (Minority carrier 2D 'x-y' solver for neutral regions) as a 2D neutral
region linear problem to characterize the normalized sidewall injected current and charge; two
parameters are thus extracted FELAT, FQLAT (Fitting parameter for sidewall injection and
charge weighting). These parameters have been defined in such a way that very reliable results are
obtained even under high current conditions without the need to repeat the 2D solution at each bias
point. These parameters remain constant unless the impurity profiles and geometry are altered
drastically. In fact, for many cases, this optional 2D solution is not necessary.
Simulation of additional 3rd dimension effects
For small near square emitter BJT structures, where lateral base current parallel to the surface
flow is highly 2 dimensional, the Extension Module RBCALC may be invoked. This gives a
2D non-linear numerical solution of majority carrier base current flow and, thus, converts
Bipole3 into a highly accurate simulator, including this significant 3rd dimension effect. The
execution time is increased by roughly a factor of 10 but is still about 10 times faster than ‘full 2D’
simulators.
Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December 2011
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11. Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla
References
1.
2.
3.
4.
Bipole3 v.4.6. (2003) User's Manual. Bipsim.Cor.
Bipole3 v.5.2U, February 2005, Reference Manual. Bipsim.Cor.
Bipole3 v.5.2, November 2008, Tutorial Guide. Bipsim.Cor.
Barlas D.; Henderson G; Zhang X; Bopp M.; Schuppen A., June 1, 1999, SiGe Transistor
Technology for RF Application, Microwave Jurnal, 1999, vol. 42 No. 6.
5. Hueting, R.J.E; Slotboom J.W; Pruijmboom A; de Boer, W.B; Timmering, C.E; Cowern,
N.E.B. September 1996, On the Optimization of SiGe – Base Bipolar Transistors – IEEE
Transactions on Electron Devices, Vol. 43, No. 9.
6. Julian, E.S. Hartanto, D. 2002, Simulations of SiGe HBTs to Obtain High fT and fMAX,
Semiconductor Electronics, 2002. Proceedings. ICSE 2002. IEEE International Conference on.
19-21 Dec. 2002. pp. 264 – 267.
Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December 2011
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12. ‫‪Design of an improved transistor performance ……………..…..Mohamed Abdultawab Abdulla‬‬
‫ﺗﺼﻤﯿﻢ ﺗﺮاﻧﺰﯾﺴﺘﻮر ذي أداء ﻣﺤﺴﻦ ﻟﻠﺘﻄﺒﯿﻘﺎت اﻟﺮادﯾﻮﯾﺔ ﺑﺎﺳﺘﺨﺪام ﺑﺮﻧﺎﻣﺞ‬
‫اﻟﻤﺤﺎﻛﺎة ﺑﯿﺒﻮل ٣‬
‫ﻣﺤﻤﺪ ﻋﺒﺪ اﻟﺘﻮاب ﻋﺒﺪ اﷲ اﻟﺒﻨﺎ‬
‫ﻗﺴﻢ اﻟﮭﻨﺪﺳﺔ اﻻﻟﻜﺘﺮوﻧﯿﺔ واﻻﺗﺼﺎﻻت ، ﻛﻠﯿﺔ اﻟﮭﻨﺪﺳﺔ، ﺟﺎﻣﻌﺔ ﻋﺪن‬
‫اﻟﻤﻠﺨﺺ‬
‫ھ ﺬه اﻟﻮرﻗ ﺔ اﻟﺒﺤﺜﯿ ﺔ ﺗﻘ ﺪم ﻣﺤﺎﻛ ﺎة ﻟﺘﺮاﻧﺰﯾﺴ ﺘﻮر ﺛﻨ ﺎﺋﻲ اﻟﻘﻄﺒﯿ ﺔ ﺑﻮﺻ ﻠﺔ ذﻛﯿ ﺔ ‪ HBT‬ﻟﻠﻌﻤ ﻞ ﻋﻨ ﺪ ذﺑ ﺬﺑﺎت ﻓﺎﺋﻘ ﺔ‬
‫اﻟﺴﺮﻋﺔ )رادﯾﻮﯾﺔ( ﺑﺎﺳﺘﺨﺪام ﺑﺮﻧﺎﻣﺞ ﻣﺤﺎﻛﺎة أﺷﺒﺎه اﻟﻤﻮﺻﻼت )ﺑﯿﺒﻮل٣(. ﻓﻲ اﻟﺒﺪاﯾﺔ ﺗﻢ ﺿﺒﻂ اﻟﻤﺤ ﺎﻛﻲ ﻋﻨ ﺪ اﻟﻘ ﯿﻢ‬
‫اﻟﻔﯿﺰﯾﺎﺋﯿﺔ ﻟﻠﺘﺮاﻧﺰﯾﺴﺘﻮر. ﺑﻌﺪھﺎ ﺗﻢ ﺿﺒﻂ اﻟﻘﯿﻢ اﻟﻔﻌﻠﯿﺔ اﻟﻤﻘﺎﺳﺔ. ﺑﻨﺎء ﻋﻠﻰ ﺗﻠﻚ اﻟﻘﯿﻢ ﻗﻤﻨﺎ ﺑﻤﺤﺎﻛﺎة اﻟﻤﺪﺧﻼت اﻟﻤﻌﻄ ﺎة‬
‫ﻟﻠﺤﺼﻮل ﻋﻠﻰ ﻣﺨﺮﺟﺎت ﻋﻤﻞ اﻟﺘﺮاﻧﺰﯾﺴﺘﻮر اﻟﻤﻌﻨﻲ.‬
‫ﻟﻠﺤﺼﻮل ﻋﻠﻰ ﺧﺼﺎﺋﺺ ﻣﺤﺴﻨﺔ ﻟﻌﻤﻞ اﻟﺘﺮاﻧﺰﯾﺴﺘﻮر ﯾﺠ ﺐ أن ﻧﺤﺼ ﻞ ﻋﻠ ﻰ ذﺑ ﺬﺑﺎت ﻓﺎﺋﻘ ﺔ اﻟﺴ ﺮﻋﺔ ‪ RF‬وھ ﻲ‬
‫ﻣﻦ أھﻢ اﻟﻤﻌﺎﻣﻼت اﻟﻌﻤﻠﯿﺔ ﻟﻠﺘﺮاﻧﺰﯾﺴﺘﻮر، ﻟﻜﻦ ھﺬا اﻟﺘﺤﺴﯿﻦ ﯾﻜﻮن ﻋﻠﻰ ﺣﺴﺎب زﯾﺎدة ﻣﻘﺎوﻣﺔ اﻟﻘﺎﻋ ﺪة ‪ RB‬وﺧﻔ ﺾ‬
‫اﻟﺠﮭﺪ اﻟﺨﻄﻲ ‪ VA‬وﻛﻼھﻤﺎ ﯾﻀﺮ ﺑﺨﺼﺎﺋﺺ أداء اﻟﺘﺮاﻧﺰﯾﺴﺘﻮر ﻋﻨﺪ اﻟﺬﺑﺬﺑﺎت ﻓﺎﺋﻘﺔ اﻟﺴﺮﻋﺔ.‬
‫ﻟ ﺬا ﻓ ﺎن ﺗﺨ ﺪﯾﺮ ﻗﺎﻋ ﺪة اﻟﺘﺮاﻧﺰﯾﺴ ﺘﻮر ﺑﺘﺮﻛﯿ ﺰ ﻋ ﺎ ٍ ﯾ ﺆدي إﻟ ﻰ ﺗﺤﺴ ﯿﻦ ﻛ ﻞ ﻣ ﻦ اﻟﺠﮭ ﺪ اﻟﺨﻄ ﻲ اﻟﻤﺮﺗﻔ ﻊ ﺑﺴ ﺒﺐ‬
‫ل‬
‫اﻟﺘﺤﻮﯾﺮ اﻷﻗﻞ ﻟﻤﻨﻄﻘﺔ اﻟﻔﺮاغ داﺧﻞ اﻟﻘﺎﻋﺪة اﻟﻤﺤﺎﯾﺪة، وﻛﺬا ﺷﻜﻞ اﻟﻀﻮﺿﺎء اﻟﺪاﺧﻠﻲ ﻋﻨ ﺪ اﻟﻤﺨ ﺮج ‪ NF‬اﻟﻤ ﻨﺨﻔﺾ‬
‫ﺑﺴ ﺒﺐ ﻣﻘﺎوﻣ ﺔ اﻟﻘﺎﻋ ﺪة اﻟﻤﻨﺨﻔﻀ ﺔ وﻣﻌﺎﻣ ﻞ ﺗﻜﺒﯿ ﺮ اﻟﺘﯿ ﺎر ‪ β‬اﻟﻤﺮﺗﻔ ﻊ اﻟﻠ ﺬﯾﻦ ﯾﺘﺮﺟﻤ ﺎن إﻟ ﻰ أداء ﻣﺤﺴ ﻦ ﻟﺘﻄﺒﯿﻘ ﺎت‬
‫ذﺑﺬﺑﺎت اﻟﺴﺮﻋﺔ اﻟﻔﺎﺋﻘﺔ.‬
‫اﻟﻜﻠﻤﺎت اﻟﻤﻔﺘﺎﺣﯿﺔ: ﺗﺮاﻧﺰﯾﺴﺘﻮر اﻟﻮﺻﻠﺔ اﻟﺬﻛﯿﺔ، ﺧﻠﯿﻂ ﺳﻠﯿﻜﻮن ﺟﺮﻣﺎﻧﯿﻮم، ذﺑﺬﺑﺎت ﻋﺎﻟﯿﺔ، ﺑﯿﺒﻮل٣.‬
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‫1102 ‪Univ. Aden J. Nat. and Appl. Sc. Vol. 15 No.3 –December‬‬