an x-band low noise inp-hbt vco with separate optimized varactor layers
DESCRIPTION
An X-Band Low Noise InP-HBT VCO with Separate Optimized Varactor Layers. T. Magrisso (1) D. Elad (1) N. Buadana (1) S. Kraus (2) D. Cohen Elias (2) A. Gavrilov (2) S. Cohen (2) D. Ritter (2). (1) RAFAEL, Armament Development Authority Ltd., Microelectronic Directorate - PowerPoint PPT PresentationTRANSCRIPT
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High Speed Electronics GroupFaculty of Electrical Engineering
(1 )RAFAEL, Armament Development Authority Ltd., Microelectronic Directorate(2 )Department of Electrical Engineering, Technion-Israel Institute of Technology
T. Magrisso T. Magrisso (1)(1)
D. Elad D. Elad (1)(1)
N. Buadana N. Buadana (1)(1)
S. Kraus S. Kraus (2)(2)
D. Cohen Elias D. Cohen Elias (2)(2)
A. Gavrilov A. Gavrilov (2)(2) S. Cohen S. Cohen (2)(2) D. Ritter D. Ritter (2)(2)
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High Speed Electronics GroupFaculty of Electrical Engineering
InP Based VCOsInP Based VCOs
• Record frequencies• Optoelectronic integration: Optoelectronic Oscillitor, Clock recovery, etc..
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High Speed Electronics GroupFaculty of Electrical Engineering
Previous work on InP HBT circuits at TechnionPrevious work on InP HBT circuits at Technion::
75 GHz TWA 43 GHz integrated TWA photoreceiver
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High Speed Electronics GroupFaculty of Electrical Engineering
Varactors in InP HBT VCOsVaractors in InP HBT VCOs
• Previous InP HBT VCOs used base collector layers as varactor layers.
• Optimized HBT requires fully depleted collector at Vbc=0, for minimum VCO’s phase noise.
• As a results, small tuning range is obtained
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High Speed Electronics GroupFaculty of Electrical Engineering
InP Semi-insulating Substrate
Ga InAs N+ Sub-Collector
Ga InAs N Collector
Ga InAs P BaseInP N+ Emitter
N+
NP
N
N+
NP
Conventional InP HBT technologyConventional InP HBT technology
10um
1um
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High Speed Electronics GroupFaculty of Electrical Engineering
Separate varactor layersSeparate varactor layers
• Varactors and HBTs can be separately optimized.
• Varactor layers can be grown either above or underneath the transistor layers.
• Varactor layers underneath transistor layers complicate interconnect.
• Varactor layers above transistor layers require stepper technology.
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High Speed Electronics GroupFaculty of Electrical Engineering
InP Semi-insulating Substrate
InP N+ Varactor Connect
InP N Varactor NGa InAs P BaseInP N+ Sub-Collector
InP N CollectorGa InAs P Base
InP N+ Emitter
N+
NP
N+
NP
N
InP HBT technology with Separate Varactor LayersInP HBT technology with Separate Varactor Layers
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High Speed Electronics GroupFaculty of Electrical Engineering
This WorkThis Work
• Carried out by contact lithography-varactor layers underneath transistor layers. • Wide tuning range Colpitts X band VCO demonstrated as first attempt.
• Simplified VBIC transistor model predicts well VCO’s performance.
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High Speed Electronics GroupFaculty of Electrical Engineering
Transistor PropertiesTransistor Properties
•Ft=180 GHz
•Fmax=200GHz
•Vturn-on=0.5V
•Vce-breakdown=5V
•Ic max )Vce=3v(=30mA
•βAC=50
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High Speed Electronics GroupFaculty of Electrical Engineering
Transistor ModelingTransistor Modeling
• DC Measurements and s-parameters
• Small-signal equivalent circuit parameters extraction.
• Degenerate VBIC model with 18 parameters only
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High Speed Electronics GroupFaculty of Electrical Engineering
VBIC large signal modelVBIC large signal model
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High Speed Electronics GroupFaculty of Electrical Engineering
VBIC model parameters extracted at specific biasVBIC model parameters extracted at specific bias , ,Does it work for large signal VCO modelingDoes it work for large signal VCO modeling? ?
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High Speed Electronics GroupFaculty of Electrical Engineering
Varactor Design & ModelingVaractor Design & Modeling
Varactor's C)V( [20X30um]
0
0.2
0.4
0.6
0.8
1
0 1 2 3 4 5
Voltage [V]
Ca
paci
tanc
e [p
F]
BC layers, Nd=1E16
New layers, Nd=1E17 Separate
We have compared 2 types of varactors:
1. Base-Collector layers.
2. Separate layers with Nd=1017 cm-3.
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High Speed Electronics GroupFaculty of Electrical Engineering
Varactor ModelingVaractor Modeling
• Different size varactors, for scaleable model extraction.
• Semi-lumped model
• Rectangular varactors achieving 1 ohm series resistance.
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High Speed Electronics GroupFaculty of Electrical Engineering
Varactor modelingVaractor modeling
Using simple model with text book equations.
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High Speed Electronics GroupFaculty of Electrical Engineering
VCO schematics – Colpitts configurationVCO schematics – Colpitts configuration
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High Speed Electronics GroupFaculty of Electrical Engineering
Vout
VE
VB
RR5R=50 Ohm
VARVAR4Vtune=4
EqnVar
HBT_Model_NL_Biased_3212X68Vcc=6
ParamSweepSweep1
Step=5Stop=20Start=0SimInstanceName[6]=SimInstanceName[5]=SimInstanceName[4]=SimInstanceName[3]=SimInstanceName[2]=SimInstanceName[1]="HB1"SweepVar="Vtune"
PARAMETER SWEEP
HarmonicBalanceHB1
OscPortName="Osc1"OscMode=yesMaxShrinkage=1.0e-5MaxStepRatio=400StatusLevel=2Order[1]=5Freq[1]=8 GHz
HARMONIC BALANCE
EM_ind3_10X61
3
21
HBT_Varactor_3196X64VR=Vtune
12
VCO_2ind_4_cap_resX51
21
I_ProbeIout
BE_capX44
2
4
1
5
3
VCO_collector_cap_N3X69
2
4
1
3
OscPortOsc1
MaxLoopGainStep=FundIndex=1Steps=100NumOctaves=3Z=2 OhmV=
Full EM SimulationFull EM Simulation
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High Speed Electronics GroupFaculty of Electrical Engineering
Testing VCOTesting VCO
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High Speed Electronics GroupFaculty of Electrical Engineering
Simulation vs. Measurments
7.8
8
8.2
8.4
8.6
8.8
9
0 0.5 1 1.5 2 2.5 3 3.5 4
Voltage [V]
Fre
q. [
GH
z]
Measurment
Simulation
Comparison between Measurement and Comparison between Measurement and Simulation with degenerate VBIC model Simulation with degenerate VBIC model
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High Speed Electronics GroupFaculty of Electrical Engineering
Measured phase noiseMeasured phase noise
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High Speed Electronics GroupFaculty of Electrical Engineering
Phase Noise SimulationPhase Noise SimulationPhase noise parameters extraction for VBIC model
Kfn=1E-12
Afn=1
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High Speed Electronics GroupFaculty of Electrical Engineering
ConclusionsConclusions
• InP HBT X band VCO with separate varactor layers underneath transistor layers achieved tuning range of 12% and phase noise of -94dB/Hz at 100KHz.
• Future work: VCO layers on top of transistor layers for higher frequencies, and optoelectronic applications. .
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High Speed Electronics GroupFaculty of Electrical Engineering
AcknowledgementAcknowledgementWe would like to thank …..
• Dr. David Rosenfeld for supporting the project.
• Rafael Microelectronic Direcrotate Design groupe and Testing House.
• Technion Russell Berrie Nanotechnology Institute.
• Liron Arazi and Kochavi Shemuel for design and testing assistance.
• Dr. Asher Madjar.