new analytic dc models for tunnel diode and resonant tunneling diode chien m. ta (sma) fujiang lin...
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NEW ANALYTIC DC MODELS FORTUNNEL DIODE AND RESONANT TUNNELING DIODE Chien M. Ta (SMA)
Fujiang Lin (IME)
Subhash R. Chander (IME)
SYMPOSIUM ON ELECTRONICSJune 2004
June 04, 2004 Symposium on Electronics 2004 2
Outline
• Introduction
• Literature reviews
• Approach and tools
• Achievements
• Remarks and discussions
June 04, 2004 Symposium on Electronics 2004 3
Introduction
• Motivations– UWB system design
– Currently, no RTD’s model in commercial EDA
tools
• Objectives– Analytic expressions for the I-V characteristic
curves of TD and RTD
June 04, 2004 Symposium on Electronics 2004 4
ReviewsExisting models
– Piecewise linear model (Tai-Haur Kuo et al., Ralph P. Santoro)
– Polynomial fit model (M. R. Deshpande et al.)
– Gaussian-exponential combination (Zhixin Yan and M.J.Deen)
– Physics-based model (J. N. Schulman et al.)
I-V characteristic
I
V
Iv
Ip
Vp Vv
What are the interesting features of tunnel diode and resonant tunneling diode?
• Negative differential resistance (NDR)
• Fast
• Temperature insensitivity
June 04, 2004 Symposium on Electronics 2004 5
Modeling• Analytical approach
• Tools: MATLAB, IC-CAP
VDID
+ -
ID = f(VD)
VD+ -
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Methodology
I-V characteristicmeasurement
Mathematic analysis
Model proposal
Simulation
Compare
Final modelSatisfactory match
Unsatisfactory match
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TD modeling - Measurement
IC-CAP setup for measuring I-V characteristic
Measured I-V characteristic
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Analytic model DFWDDNDRDREVDD VIVIVIVI
1exp_
TREV
DREVSDREV Vn
VIVI
REVSFWDS
PDD
PPDNDR
II
VVAAV
AVIVI
__
1exp
2
1exp_
TFWD
DFWDSDFWD Vn
VIVI
where
I
V
Iv
Ip
Vp Vv
Is_rev
nrevIpVp
A
Is_fwd
nfwd
I-V characteristic
June 04, 2004 Symposium on Electronics 2004 9
SimulationParameter Extracted value Optimized value
Is_rev 95.21 x 10-6 525 x 10-6
nrev 1.001 3.011
Is_fwd 90.51 x 10-6 73.16 x 10-6
nfwd 7.021 6.339
Vp 80 x 10-3 40.57 x 10-3
Ip 372.3 x 10-6 494.5 x 10-6
A 10 13.83
Final RMS error = 0.95%
Maximum error = 2.28%
I-V characteristic with extracted values
I-V characteristic with optimized values
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New model for resonant tunneling diode
DFWDDNDRDD VIVIVI
DDDNDR VVAVI exp1
1exp
T
DSDFWD Vn
VIVI
where
I
V
Iv
Ip
I-V characteristic
ISn
A
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Simulation
Parameter Optimized values
A 652.7x10-9
2.719
16.92
2.593
IS 2.2248x10-19
n 0.7882
Final RMS error = 3.813%
Simulation result
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Symmetric characteristics for RTD DREVDFWDDNDRDD VIVIVIVI
DDDDNDR VVVAVI exp
1exp
T
DSDFWD nV
VIVI
1exp
T
DSDREV nV
VIVI
where
Simulation result
Symmetric I-V characteristic
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One model for both TD and RTD ?
ParameterOptimized
values
A 831.3x10-6
0.2883
1.091
16.67
IS 108.9x10-6
n 7.146
Final RMS error = 1.03%Recognizable deviation in the reverse-biased region (not very critical since the devices are usually biased in the NDR region)
Not much degradation compared to 0.95% RMS error of the TD’s model
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Remarks, conclusion, and future works• Remarks
– Excellent match between simulation and measurement: RMS error is
less than 1% for TD and 3.8% for RTD
– Need accurate measurement, especially for ac modeling: de-
embedding technique
– Need modification to have scalability
• Conclusion
– The new DC model for the RTD is sufficient to describe the
behaviors of the devices
• Future works– AC model expansion
– Implementation into EDA tools
– Coding in Verilog-A
June 04, 2004 Symposium on Electronics 2004 15
THANK YOU