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

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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

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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