NEW ANALYTIC DC MODELS FOR TUNNEL DIODE AND RESONANT TUNNELING DIODE

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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 ELECTRONICS
• June 2004

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Outline

• Introduction
• Literature reviews
• Approach and tools
• Achievements
• Remarks and discussions

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Introduction

• Motivations
• UWB system design
• Currently, no RTDs model in commercial EDA tools
• Objectives
• Analytic expressions for the I-V characteristic
  curves of TD and RTD

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Reviews
What are the interesting features of tunnel diode
and resonant tunneling diode?

• Existing 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

• Negative differential resistance (NDR)
• Fast
• Temperature insensitivity

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Modeling

• Analytical approach
• Tools MATLAB, IC-CAP

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Methodology
I-V characteristicmeasurement
Mathematic analysis
Model proposal
Unsatisfactory match
Simulation
Compare
Final model
Satisfactory 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
where
I-V characteristic
Is_fwd nfwd
Is_rev nrev
Ip Vp A
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Simulation
Parameter 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
where
I-V characteristic
A ? ? ?
IS n
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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
Simulation result
Final RMS error 3.813
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Symmetric characteristics for RTD
where
Symmetric I-V characteristic
Simulation result
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One model for both TD and RTD ?
Parameter Optimized values
A 831.3x10-6
? 0.2883
? 1.091
? 16.67
IS 108.9x10-6
n 7.146
Recognizable deviation in the reverse-biased
region (not very critical since the devices are
usually biased in the NDR region)
Final RMS error 1.03
Not much degradation compared to 0.95 RMS error
of the TDs 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

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• THANK YOU