Three-Dimensional Electro-Thermal Circuit Model of Power ...mos-ak.org/bucharest/presetnations/Chvala_MOS-AK_Bucharest.pdf · Three-dimensional electro-thermal circuit model of power

Slovak University of TechnologyInstitute of Electronics and Photonics

MOS-AK WorkshopBucharest 2013

Three-Dimensional Electro-Thermal Circuit Model of Power Super-Junction

MOSFET

Sep. 20, 2013 Bucharest MOS Modeling and Parameter Extraction Working Group11th MOS-AK/GSA ESSDERC ESSCIRC Workshop

Aleš Chvála

Slovak University of Technology in Bratislava



Motivation

Development and calibration of electro-thermal MOSFET model for power technology



Outline

• Introduction

• Electrical compact model of Super Junction MOSFET

• Electrical equivalent of three-dimensional thermal system

• Experiment and model verification (UIS test)

• Conclusions



• Circuit simulators are standard tools in the development and optimization of electronic systems

• SPICE-like models provide faster results but in general do not take into account nonlinear thermal dependences of certain parameters

• Properties of power semiconductor devices are very strongly temperature-dependent

• Self-heating and dynamic interdependence between electrical and thermal components of corresponding model need to be implement

INTRODUCTION



Super Junction MOSFET – high voltage technology (BV ~ 600V)

For analysis novel locally charge balancedtrench based super-junction n-channelpower MOSFET was used. Samples exceedV(BR)DSS ~ 600 V, VGSTH = 4 V,RON = 23mΩ/cm2 and single pulse drain-to-source avalanche energy EAS = 800 mJ forL = 10mH

ELECTRICAL COMPACT MODEL

T. Fujihira, “Theory of Semiconductor SuperJunction Devices,” Jpn J. Appl. Phys, 36(10), pp. 6254-6262, 1997.

P. Moens, et al., “UltiMOS: A Local Charge-Balanced Trench-Based 600V Super-Junction Device,” proc. of the 23rd International Symposium on PowerSemiconductor Devices & ICs, ISPSD, pp. 304-307, 2011.



Die

Lead framePackage

S D

G

ELECTRICAL COMPACT MODELSuper Junction MOSFET

2D doping concentration DPAK2 package



Thermal systemElectrical circuit

PowerPower

Temperature

Circuit electro-thermal model

INTRODUCTION

Interaction between electrical and thermal parts



Gate

CGD RD

RSCGS

DB

VBRRL

VT0 - threshold voltageRD - drain resistivityDB - body diodeVBR - breakdown voltageRL - leakage resistanceSBURN - thermal burning

CDSVT0

RBR

RDB

=f(Temperature)

SBURN

PowerPower

Temperature

Thermal system

Simple model + Real device effects


SPICE Level...BSIM...

Drain

Source



Breakdown characteristicsof SJ MOSFET

Transfer characteristicsof SJ MOSFET


T (K)



CV characteristics of SJ MOSFET


Measurement setup for CGS, CGD

and CDS measurements

H.Suto et.al, 'Methodology for Accurate C-V Measurements of GateInsulators below 1.5nm EOT', Extended Abstracts of the 2002 Int'l Conf. on Solid State Devices and Materials, Nagoya, pp. 748-749



Thermal destruction (SBURN)


BLACKBURN, D. L. Power MOSFET failure revisited, In Power Electronics Specialists Conference PESC '88, Kyoto, Japan, 1988, pp. 681-688.

Donoval, D., Vrbicky, A., Marek, J., Chvala, A., Beno, P., "Evaluation of the ruggedness of power DMOS transistor from electro-thermal simulation of UIS behaviour", Solid-State Electronics, 52, pp. 892-898, 2008.

Destructive energy3/4 vs. starting temperature and respective extrapolation of maximum device temperature

Estimate of device temperature from VDS(Breakdown) = f(temperature)



Source

Drain

Gate

CGD RD

RSCGS

DB

VBRRL

VT0 - threshold voltageRD - drain resistivityDB - body diodeVBR - breakdown voltageRL - leakage resistanceSBURN - thermal burning

CDSVT0

RBR

RDB

=f(Temperature)

SBURN

PowerPower

Temperature

Thermal system

Simple model + Real device effects

SPICE Level...BSIM...

EQUIVALENT THERMAL CIRCUIT



Thermal system

d1

d2

d3

P(t) A

Cth1

Cth2

Cth3

Rth1

Rth2

Rth3

Tj

Heat sink T(0,t)

- Power

- Junction temperature

- Thermal capacity

- Thermal resistivity

Electrical equivalent

P(t) [W] ~ I(t) [A]Tj [K] ~ VTj [V]Cth [Ws/K] ~ C [F]Rth [K/W] ~ R [Ω]

A

dRR i

ithi

AdcCC iithi

VTj




Thermal coefficients RC network with constant element

RC network with temperaturedependent resistances

2cTbTa

- constant

A

dRR i

ithi

Si – strong temperature dependent

T(K) 300 400 500

c(J/(K cm-3) (W/cmK)

Si 1.63 1.55 1.09 0.82

Cu 3.42 4.01 4.00 3.98

takes into account temperature dependence of thermal conductivity




ii

ithxi

zy

xRR

xi

iiithi zyxcCCi

| xi |

__

yi

__ __zi

__

| xi | | xi |

__

yi

__

iR

2

iC

2

xiR

4

iC

8

iC4

xiR

1-D 2-D 3-D

Multi-dimensional thermal flow





8 x 8 MOSFETs are connected taking intoaccount parasitic resistances of thepoly-Si gate electrode and metal sourceelectrode

Heat distribution at avalanche conditions



Thermal equivalent network

VT0 - threshold voltageRD - drain resistivityDB - body diodeRL - leakage resistanceVBR - breakdown voltageSBURN - thermal burning

Electrical circuit

CDS

CGD =f(VDS)CGS

=f(VTj)

COMPACT MODEL OF POWER MOSFET



EXPERIMENT AND MODEL VERIFICATION

Simplified UIS test circuit and current and voltage waveforms of the tested device under UIS test conditions

dti(t)VEAVt

(BR)effAS 0

0 , 2

1 2 S ASAS RLIE

Unclamped Inductive Switching (UIS) test



Model with temperature-dependent RC network bettercorresponds the measurement

UIS test characteristics of the SJ MOSFET


Measurement

Temperature-dependent RC network

Standard RC network



Comparison of destructive currents for different values of inductances


UIS test characteristics of the SJ MOSFET

Suitable thermal properties andanalysis provide realistic results




Multipulse UIS test characteristics of the SJ MOSFET

Temperature distribution at thebeginning of the tenth UIS pulseinside the structure




Multipulse UIS test characteristics of the SJ MOSFET

Current density distribution at thebeginning of the tenth UIS pulseinside the structure



Conclusions

Three-dimensional electro-thermal circuit model of power Super-Junction MOSFET was introduced.

Implementation of real device effects and appropriate thermal properties are important for correct simulations results.

The simulations with implemented three-dimensional thermal flow and distributed properties of the power MOSFET provide more accurate results.



Thank you for your attention

Acknowledgements This work has been done with support of 7FP project SMAC, no. 288827

and grant VEGA 1/0866/11.

Three-Dimensional Electro-Thermal Circuit Model of Power ...mos-ak.org/bucharest/presetnations/Chvala_MOS-AK_Bucharest.pdf · Three-dimensional electro-thermal circuit model of power

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