Electrothermal modeling of IGBT’s: Application to short ...

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Electrothermal modeling of IGBT’s: Application toshort-circuit conditions

Anis Ammous, Kaiçar Ammous, Hervé Morel, Bruno Allard, DominiqueBergogne, Fayçal Sellami, Jean-Pierre Chante

To cite this version:Anis Ammous, Kaiçar Ammous, Hervé Morel, Bruno Allard, Dominique Bergogne, et al.. Elec-trothermal modeling of IGBT’s: Application to short-circuit conditions. IEEE Transactions on PowerElectronics, Institute of Electrical and Electronics Engineers, 2000, 15 (4), pp.778-790. �hal-00140098�

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778 IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 15, NO. 4, JULY 2000

Electrothermal Modeling of IGBT’s: Application toShort-Circuit Conditions

Anis Ammous, Kaiçar Ammous, Hervé Morel, Bruno Allard, Member, IEEE, Dominique Bergogne, Fayçal Sellami,and Jean Pierre Chante, Member, IEEE

Abstract—This paper discusses the possible estimation of IGBTfailure phenomena by mean of simulation. The studied destructionmode addresses the large surges, especially the short-circuit ofIGBT’s. In this case the reason of the device destruction is athermal runaway. Thus we have developed an electrothermalmodel of the IGBT. The developed model may be implemented inany circuit simulators featuring a high level description language(SABER, ELDO, SMASH, PACTE ). The used electrical modelis based on the Hefner model of the IGBT. A bidimensional finiteelement thermal model is considered. This model has been opti-mized to gives a good trade-off between accuracy and simulationcost. To validate the implemented model, finite element simula-tions have been performed with the ATLAS two-dimensional (2-D)numerical simulator. The study is completed with the comparisonbetween experimental and simulation results. It is shown that theproposed electrothermal model allows the prediction of the IGBTdestruction phases in the case of large surges. So, users of IGBTcomponents have the possibility to estimate, by mean of simula-tion, the possible failure (due to large surges) of these devices inthe case of complex converters. This enables the possibility fordeveloping protection systems for IGBT’s without any destructivetest.

Index Terms—Electrothermal modeling, failure, IGBT, numer-ical simulation, short-circuit.

NOMENCLATURE

(cm ),(cm)

Effective area and length of the semiconductor de-vice.Silicon specific heat (J/g/K).Base-collector depletion capacitance (F).Collector-emitter redistribution capacitance (F).Drain-source depletion capacitance (F).Gate-drain capacitance (F).Gate-drain overlap depletion capacitance (F).Gate-source capacitance (F).Oxide capacitance per unit area (F/cm ).Gate-drain overlap oxide capacitance (F).Ambipolar diffusivity (cm /s).Carrier-carrier scattering diffusivity (cm /s).Anode current (A).Charge control base current (A).Charge control collector current (A).

Manuscript received January 25, 1999; revised March 21, 2000. Recom-mended by Associate Editor, W. M. Portnoy.

A. Ammous and F. Sellami are with the Power Electronic Laboratory (LEP),Ecole Nationale d’Ingénieurs de Sfax (ENIS), Sfax, Tunisia.

K. Ammous, H. Morel, B. Allard, D. Bergogne, and J. P. Chante are with theCentre de Génie Electrique de Lyon (CEGELY), UMR 5005 CNRS, Institut Na-tional des Sciences Appliqués (INSA) de Lyon, Villeurbanne F-69621, France.

Publisher Item Identifier S 0885-8993(00)05574-5.

Thermally generated leakage current (A).Mosfet current (A).Multiplication current (A).Thermal conductivity (W/cm/K).Boltzmann constant (J/cm /K).Linear region MOSFET transconductance param-eter (A/V ).Saturation region MOSFET transconductance pa-rameter (A/V ).Ambipolar diffusion length (cm).Electron concentration (cm ).Effective LDB (Low Doped Base) doping level con-centration (cm ).Acceptor impurity level concentration (in thebody) (cm ).Doping level concentration in the base (cm ).Collector-base space charge concentration (cm ).Velocity saturation component of (cm ).Intrinsic carrier concentration (cm ).Hole concentration (cm ).Excess carrier concentration (cm ).

at HDB (Highly Doped Base) edge of the LDB(cm ).

at emitter edge of the HDB (cm ).Input dissipated power (W).Electron charge (C).Total excess carrier base charge (C).Excess carrier charge in the HDB (C).Excess carrier charge in the LDB (C).Conductivity-modulated base resistance (Ohm).Absolute temperature (K).Input temperature (K).Thermodynamic voltage (V).Anode-cathode voltage (V).Emitter-base voltage (V).Emitter-base diffusion voltage (V).Base-collector voltage (V).Base-collector breakdown voltage (V).Drain-gate voltage (V).Gate-source voltage (V).Flat band voltage (V).Quasineutral LDB width (cm).Metallurgical LDB width (cm).Base-collector depletion width (cm).Drain-source depletion width (cm).Gate-drain overlap depletion width (cm).Metallurgical width of HDB (cm).

0885–8993/00$10.00 © 2000 IEEE

AMMOUS et al.: ELECTROTHERMAL MODELING OF IGBT’S 779

Effective width for base transport (cm).Corresponding (when breakdown occurs) forNPT (Non Punch-Trough) structure (cm).Silicon mass density (g/cm ).Electron, hole mobilities in the base (cm /V/s).Carrier-carrier scattering mobilities (cm /V/s).Current gain of internal PNP bipolar transistor in-side the IGBT.Substrate Fermi potential (V).Silicon permittivity (F/cm).High-level injection lifetime in the base (s).High-level injection lifetime in LDB (s).Effective lifetime in depletion region (s).Transverse field transconductance factor (V ).

I. INTRODUCTION

THE main component of the heat generation inside a semi-conductor device is equal to the scalar product of the elec-

tric field by the current density. The heat generation becomesmore critical in the case of large surges specially in short-cir-cuit conditions.

Literature shows some studies about the electrothermalmodeling of the IGBT to evaluate the effect of the deviceself-heating on the electrical characteristics [1]–[6]. In thesestudies the thermal model is a classical unidimentionnal modelbased on the finite difference method (with a little number ofnodes) which is not adapted to the case of IGBT large surgesoperation [7]. Indeed to avoid a large error on the estimationof the device temperature in the case of a large surge, ahigh number of nodes is required. Moreover, in these studieselectrothermal modeling is performed by evaluating physicalparameters as functions of unique junction temperature. Really,the evaluation of the electrical parameters as functions of tem-perature depends on the local region where the correspondingphysical phenomenon takes place. Specially, in the case of largesurges, the temperature gradient inside the IGBT is high andthe temperature distribution is bidimentionnal at least [8]–[10].So, many internal temperatures in the device should be takeninto account in the electrical model.

The present paper covers a study about the estimation ofIGBT failure phenomena, by mean of simulation. An elec-trothermal model of the IGBT is then developed. The modelhas been implemented in the circuit simulator PACTE [11].We note that it is possible to implement the proposed model inany other circuit simulator featuring a high-level descriptionlanguage like SABER [12], ELDO [13] or SMASH [14] .Section II covers the presentation of the electrical modelof the IGBT, based on the A. Hefner model [15], [16]. Thismodel, based on semiconductor device equations, gives a gooddescription of the IGBT electrical behavior. A bidimensionalthermal model is proposed in Section III. This model is athermal network based on the finite element method.

To justify the geometrical description of the thermal model, aone half of a symmetric IGBT cell is investigated using the gen-eral-purpose numerical device simulator ATLAS two-dimen-sional (2-D) [17].

Finally, physical parameters have been evaluated using thedifferent local temperature throughout the device (Section IV).Comparisons between numerical simulations, experimental

Fig. 1. Schematic one-half of symmetric IGBT cell and its simplifiedequivalent electrical circuit used to develop the electrical model.

results and their equivalent electrothermal circuit simulationsshow that the estimation of the IGBT failure, in the case oflarge surges, is possible by mean of simulation.

II. ELECTRICAL MODELING

The electrical model of the power insulated gate bipolar tran-sistor by Hefner [15], [16] has been used. This model gives agood description of the IGBT behavior specially in the case ofsteady-state and quasi-static operating conditions. The model isbased on the equivalent circuit of a MOSFET which supply thebase current to a NPN bipolar transistor [18]. The schematic ofhalf of a symmetric IGBT cell with the basic principles of thecircuit model are shown in Fig. 1. When the emitter-base junc-tion is forward biased, holes are injected into the epitaxial layer

from the substrate . The hole concentration injectedin the base (at the emitter-base junction limit) is given by theclassical relation

(1)

where is the hole concentration in the base at the thermody-namic equilibrium.

Since the epitaxial layer is much less doped than the substrate,then this yields the high-level injection of holes in the base

. If the total current density is assumed to be uniform inthe base, the ambipolar diffusion equation is given by [15], [16]

(2)

with .


Fig. 2. Experimental and simulated circuit used to perform dynamic and staticcharacteristics of the studied IGBT’s.

The IGBT electrical model takes into account the carriermultiplication and thermal generation phenomena within thebase-collector depletion region. Indeed, the carrier multiplica-tion phenomenon is characterized by the multiplication factor

approximated by the following empirical expression [18].

(3)

The parameters and depend mainly on the doping level ,and the breakdown voltage, .

The thermally generated leakage current is given by [19]

(4)

where is the base-collector depletion width.Further details about the IGBT analytical model may be

found in [15], [16] and [20]–[23]. The expressions used todescribe the PT IGBT model have been listed in Appendix 1.

The electrical circuit used in simulation and experimentis shown in Fig. 2. The experimental and simulation results,obtained for two devices and their corresponding electricalmodels, are given in Figs. 3–5. The model parameters for thetwo devices have been obtained with an identification proce-dure based on the fitting of experimental static and dynamiccharacteristics [24].

Fig. 3 shows the current–voltage (I–V) characteristic of theIRGBC 20U (13 A/600 V) for different gate-to-source voltagevalues for isothermal conditions ( K). Figs. 4 and 5gives the transient switching characteristics for isothermal con-ditions ( K) of the IRGBC 20U and the BUP 202(15 A/1000 V) devices, respectively. The different waveforms

, and show the good agreement between experi-mental and simulation results. So, that confirms that the elec-trical model, developed by Hefner, covers a large physical de-scription of the different phenomena inside the IGBT. Then itmay be used in the developed electrothermal model.

All the electrical model parameters corresponding to theIRGBC 20U and the BUP 202 devices are given in Appendix 2.

III. THERMAL MODELING

A. State of the Art

Because most of the semiconductor device models are imple-mented in circuit simulators, thermal circuit networks are the

Fig. 3. Experimental and simulation static characteristic of the IRGBC 20Uobtained for different gate-to-source voltage values.

practical models for electrothermal simulations. Literature pro-poses some approaches to construct thermal networks equiva-lent to a discretization of the heat equation. For example thefinite difference method (FDM) [3]–[25] and the finite elementmethod (FEM) [7]–[26] are proposed.

In the case of vertical power devices, where the thicknessis small compared to other dimensions, it is commonly con-sidered that heat is generated at the top surface of silicon andflows uniformly along the -axis (perpendicular to the siliconsurface). So, the top surface is considered to be a geometricalboundary of the device at , where the input poweris assumed to be uniformly dissipated. The lower surface (at

) is considered to be the cooling boundary, where thetemperature is assumed to be equal to the input temperature(Fig. 6). Convection and radiation are assumed to be negligible.So a one-dimensional (1-D) heat-flow may be considered

(5)

with boundary conditions

The thermal conductivity is assumed to be equal to [3]

K(6)

Studies in [7] have shown the advantage of the finite elementmethod compared to the difference element method specially inthe case of large surges of short time duration, which is the caseof IGBT short-circuit conditions.

So we retain thermal circuit networks based on the finite ele-ment method.

B. Electrothermal Simulation of the IGBT With NumericalSimulations

This section presents the IGBT electrothermal behavior in thecase of short-circuit conditions. This study is performed with


Fig. 4. Current and voltage waveforms obtained with the analytical model implemented in the PACTE simulator for the device IRGBC 20U inside the circuit inFig. 2. (a) , H, V and (b) , H, V and .

the ATLAS 2-D numerical device simulator [17]. This bidimen-sional study takes into account the coupled transport of heat andcharge carriers which is based on the self consistent solutionof Poisson’s equation, the continuity equation for electrons andholes and the heat flow equation in space and time.

Half of a symmetric IGBT cell is investigated (Fig. 7). Col-lector-to-Emitter voltage is fixed at 400 V, and 16 V is ap-plied between gate and emitter. The device temperature distri-bution obtained by simulation is pictured in Fig. 8 after 13 sof short-circuit conditions.

As a thermal boundary condition for the simulation, a heatsink held at 300 K is attached to the bottom of the device.

Fig. 8 shows that the highest temperature reached in the IGBThalf-cell is located at the end of the channel and near the inter-cellular region. The temperature distribution is bidimentionnaldown to 20 m from the top of the cell and the temperature maybe considered as unidimentionnal in the rest of the structure.These observations are important to build an economic thermalmodel. However, a 1-D thermal model is not sufficient to predictthermal runaway of the IGBT under large surges, because the

power is not uniformly dissipated at the top of the device. Themajor part of power is dissipated at the end of the channel. Thispower results from a high electric field and high current densityin this region. In the case of -channel IGBT’s the major partof the total current in the device crosses the channel. It is anelectron current (the gain of the internal PNP transistoris low). The latter analysis enables to construct a substantialthermal model adapted to the large surge conditions.

C. IGBT Thermal Model

As mentioned here-above, the proposed thermal model of theIGBT, should suit well with circuit simulators and should enableto predict the IGBT temperatures in the case of large powersurges. So, a bidimensional thermal networks equivalent to adiscretization of the heat equation by the finite element methodis developed.

Studies in [7] and [26] show that the 1-D equivalent thermalnetwork obtained by the finite element method may be repre-sented by the circuit in Fig. 9.


Fig. 5. Current and voltage waveforms obtained with the analytical modelimplemented in the PACTE simulator for the device BUP 202 inside the circuitin Fig. 2. (C1) , H, V and(C2) , H, V and .

Fig. 6. Unidimensional semiconductor die representation considered for thethermal modeling.

Where

and

And is the discretization step.This model is obtained by a choice of linear piecewise func-

tions equal to 1 at node number and zero at any other node.In the case of a bidimensional problem, a representation of

the 2-D elements is the 2-D equivalent thermal network madeof Lagrange-type triangular elements (Fig. 10) [7]–[26].

Where

and

Fig. 7. Half of a symmetric IGBT cell structure used in the numerical simulator(ATLAS 2-D).

where are the coordinate of the node number in theaxes and are a circular permutation of the nodes 1, 2 and 3which compose the triangular element surface . The 1-D and2-D latter models may be used to represent the thermal phe-nomena inside the IGBT. Indeed the complete thermal modelis shown in Fig. 11. This model is a combination of a 1-D anda 2-D equivalent thermal network. It enables the optimizationof the simulation cost. In some ten of micrometers from the sur-face, thermal phenomena are bidimensional hence a 2-D thermalmodel is used, and beyond a 1-D thermal model is sufficient.

is the estimated length where the power is dissipated in sur-face. Because of the important temperature gradient in the de-vice, specially in the intercellular region, it is necessary to usea fine discretization mesh in this region (as shown in Fig. 11) toobtain accurate results.

The electrons flowing through the base-collector junctiongenerate heat due to their collisions with the crystal structure.The corresponding dissipated power is given by

(7)

In the same way the holes flowing through the base-collectordepletion layer generate heat by the dissipated power givenby

(8)

The equivalent power dissipated in the base resistance and inthe emitter-base depletion layer (due to carrier-crystal structurecollisions) is given by

(9)

Where is the emitter-base diffusion depletion voltage, andis the conductivity-modulated base resistance. The evalu-


Fig. 8. Temperature distribution in the IGBT half-cell, after 13 s short-circuit test, obtained by the ATLAS simulator: V and V.

Fig. 9. Unidimensional equivalent thermal networks, between two nodes,obtained by the finite element method.

Fig. 10. Bidimensional equivalent networks, for a triangular element, obtainedby the finite element method.

Fig. 11. The proposed thermal model of the IGBT.

ation of the dissipated power by the electrical model is suffi-cient to predict the temperature in the different regions inside theIGBT. So, in the following study, thermal and electrical models


are coupled to give an adequate model of the IGBT allowing anaccurate description of the electrothermal behavior.

IV. ELECTROTHERMAL MODELING

A. Temperature Dependency of the Electrical and PhysicalParameters

Physical parameters in the electrical model depend on tem-perature inside the component. Some of these parameters cor-respond to a phenomenon in different regions, which have dif-ferent temperatures, like the mobility.

So, some local temperatures are estimated from the thermalmodel and then are used in the different physical parameter ex-pressions of the electrical model. For example, the temperaturein the MOSFET channel is needed to evaluate thresholdvoltage [27] and the surface mobility [27]. Differenttemperatures in the base-collector depletion region [tempera-ture near the intercellular region and the equivalenttemperature in the middle of the base-collector depletion re-gion ] are used to evaluate thermal generation current(Fig. 8). Temperatures in the base region are needed to eval-uate conductivity-modulated base resistance, the base high-levellifetime, the mobility and the intrinsic carrier concentration. Thetemperature in the emitter-base depletion region is usedto evaluate the emitter-base diffusion depletion voltage.

It is important to note that in the case of large power surges,and when the device temperature is high, all the physical param-eter dependencies are to be taken into account.

For instance, the intrinsic concentration is given by [28]

K

K cm (10)

The thermal generated leakage current given by the expression(4) is divided on two parts depending on the effective surfacecorresponding to the intercellular region and the cellularregion . These expressions are calculated with thetemperatures and respectively (Appendix 1).

The saturation velocity of electrons and holes are given re-spectively by

K (cm/s) (11)

K (cm/s) (12)

These expressions are valid in low doped regions (in the basefor example, ).

The electrons and hole mobilities are given by Naraind Aroraand al [29] following expressions (for ). See (13) and(14) at the bottom of the page. Where (cm ) is the dopinglevel concentration ( or ) of the considered region.

Electrons and hole lifetime are given by

KK

(s) (15)

The thermodynamic voltage is given by

(16)

The threshold voltage is given by

(17)

where is the most temperature-dependent parameter givenby

(18)

The threshold voltage behavior as a function of temperature maybe obtained by experimental measurements. This characteristicis approximately linear [27].

The MOSFET current in electrical model is given by [15],[16]. See (19) at the bottom of the page, where anddepends on channel temperature .

parameter is proportional to the electron mobility in thechannel, so

K(20)

where is the value of evaluated at room tempera-ture ( K).

KK

KK cm /V/s (13)

KK

KK cm /V/s (14)

for

for

for

(19)


Fig. 12. Static characteristics, of the IGBT device, obtained by the numericalsimulator (ATLAS 2-D) and the equivalent analytical model (PACTE).

Fig. 13. Current and voltage waveforms obtained for the IGBT device, in theturn-on transient. (Electrical circuit of Fig. 2 with 400 V, ,

, and H).

The ratio is supposed to be given by [30]

(21)

from (20) and (21) we obtain

(22)

Fig. 14. Current and voltage waveforms obtained for the IGBT device, in theturn-off transient. ( V, , and

H).

The internal currents and voltages inside the IGBT are used tocalculate the power dissipation in the device. This leads to com-pute the different region temperatures inside the IGBT by thedeveloped (2-D) thermal model and so to evaluate the corre-sponding physical parameter values.

To take into account the thermal conductivity variation asfunction of temperature, the thermal resistance between twonodes is evaluated as a function of an equivalent temperature

given by

between the nodes and

In the following sections we perform the comparison betweenthe electrothermal behavior of the IGBT obtained by the analyt-ical model, the numerical simulator and the experiments.

B. Comparison with Numerical Simulation Results

The complete identification of all the technological param-eters of a real structure by numerical simulations demands toomuch time, probably several hundreds of simulation fittingphases. So we have set arbitrary values to the technologicalparameters (structure dimensions, doping level, junction depth,oxide thickness ) of half of a symmetric IGBT cell which is


Fig. 15. Short-circuit current evolution of the half of an IGBT cell, for different structure characteristics, obtained with the numerical simulator (ATLAS 2-D).(C1) ( cm , cm , the intercellular concentration is about cm ) (C2) ( cm , cm , theintercellular concentration is about cm ) (C3) ( cm , cm , the intercellular concentration is about cm ) (C4)( cm , cm , the epitaxial layer doping is homogenous).

used as a reference. Indeed, the I–V static characteristics andthe transient responses of the proposed structure is closed tothose of the device IRGBC 20U. So, we propose to establishthe corresponding electrothermal model of this proposed struc-ture. The comparison of the results given by both simulations(numerical model and the analytical model) enable to justifythe accuracy of the thermal model mesh (Section II) and theregion-temperature dependencies of the physical parameters(Section III–A).

Some electrical characteristics are shown in Figs. 12–14.They picture the comparison between the results obtained bythe numerical model (ATLAS 2-D) and the analytical model(PACTE). Fig. 12 shows the I–V characteristic for differentgate-to-source voltage values. Fig.s 13 and 14 show the elec-trical waveforms obtained by both simulations in the case of theturn-on and the turn-off transients of the IGBT, respectively,with the circuit in Fig. 2.

These results show a good agreement between the numericaland the analytical model. Some discrepancies exist between thetwo simulations specially in the case of the turn-off transients.This is mainly due to the simplifications introduced in the an-alytical model. However the latter discrepancies have to be putin balance with the significant difference in simulation cost be-tween the numerical model and the analytical model. For in-stance, the simulation using the numerical simulator (ATLAS)of the turn-off transient (Fig. 14) of half of a symmetric cellstructure has required about 8000 minutes of CPU-time on a

SparcStation 10, while the same simulation using the analyticalmodel with the PACTE circuit simulator demands about 15 s onthe same workstation.

The analytical model parameters used in the simulations, andcorresponding to the proposed structure (Fig. 7), are given inAppendix 2.

C. Short-Circuit Conditions

In the case of large power surge conditions, specially in thecase of short-circuit, the IGBT is submitted to a large dissipatedpower which induces (as mentioned in Section II) high localtemperatures throughout the device. So, the device fails verysoon if no protection circuit has been implemented.

Fig. 15 shows short-circuit currents in the IGBT, obtained bysimulation for different structures when they are submitted to400 V between drain and source and 16 V between gate andsource. Two important phases appear in the short-circuit currentbehavior. First the decrease of the current is mainly due to a de-crease of the surface mobility in the MOSFET channel when thechannel temperature is rising. Second, an increase of the currentinside the device is due to the increase of the thermally gener-ated current . The second phases is critical and the IGBTbecomes uncontrollable (the thermal runaway phenomenon es-tablishes rapidly). Fig. 16 shows the electrical and the thermalresponse behaviors obtained by both the numerical model and


Fig. 16. Short-circuit current and temperature behaviors, in the proposed halfof an IGBT cell (C1), obtained with the numerical model (ATLAS 2-D) and theanalytical model (PACTE): V and V.

analytical model in the case of short-circuit conditions. The re-sults obtained by both simulations are in good agreement. Thisdemonstrates the practical accuracy of the electrothermal modeland the physical parameter-region temperature dependencies asproposed in here-above sections.

The maximum temperature reached inside the device (whenthe short-circuit current runway begins) is about 900 K whatcorresponds to the intrinsic temperature in the doping re-gion. These observations confirm the experimental results givenin [27].

Fig. 17 shows the comparison between the experimental andsimulated results obtained for the IRGBC 20U device in the caseof a destructive short-circuit. The measured evolutions show thatthe estimation of the IGBT failure phenomenon by mean of sim-ulation, in the case of large power surge conditions, is highlypossible and largely reliable in the presented case. However theaccuracy of the proposed electrothermal model of the IGBT istributary of the accuracy of the physical parameter-temperaturedependencies established in this section. Unfortunately, some ofthese parameter dependencies remain unknown when the localtemperature exceeds 600 K. This may explain the discrepancieson critical phase behaviors obtained by the experimental test andby the analytical model.

Fig. 17. Experimental and simulated (analytical model) behavior of thecurrents and the temperature in the IRGBC 20U under short-circuit conditions:

V and V.

V. CONCLUSION

Both analytical and numerical electrothermal models of theIGBT under short-circuit, have been developed. The analyticalmodel is based on an electrical model (Hefner model) coupledwith a 2-D thermal model. The numerical model has been sim-ulated using the ATLAS-2-D simulator and so far is used as areference. The obtained results are in good agreement with mea-surements in the case of large power surge conditions, exceptwhen high temperatures are reached inside the device. This isdue to the fact that some temperature dependency expressionsof physical parameters, e.g., mobilities, are not known when thetemperature is higher than 600 K.

The numerical model is accurate but demands a preciseknowledge of all the technological parameters of the devicestructure. Moreover the simulation cost is very expensive(several day of CPU time), so it is not possible to obtain goodparameter value fittings with measurements. However it isremarkable that such a numerical model is very easy to develop(about one day of work) using a simulator like ATLAS-2-D.

Beside the analytical model has demanded a large effort tobe developed (several months), but it gives acceptable accuracywith a very short simulation cost ( s). So using such a model,measurement fitting is possible.


Hence, we have shown that analytical model may enable topredict the short-circuit behavior of IGBT’s in circuit simulator.This would be applied to the design of short-circuit protectioncircuits or to the simulation of circuit reliability.

APPENDIX 1

Expressions of the Punch-through IGBT electrical model:

for

for

See the equation at the bottom of the page.

APPENDIX 2

See Table I.

for

for

for


TABLE IELECTRICAL MODEL PARAMETER VALUES (AT ROOM TEMPERATURE) OF THE DIFFERENT DEVICES ADDRESSED IN THIS PAPER

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[16] A. R. Hefner Jr. and D. M. Diebolt, “An Experimentally verified IGBTmodel implemented in the Saber circuit simulator,” IEEE Trans. PowerElectron., vol. 9, pp. 532–542, Sept. 1994.

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[18] A. Blicher, Field-Effect and Bipolar Power Transistor Physics. NewYork: Academic, 1981, p. 312.

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steady-state and transient characteristics of power insulated-gate bipolartransistor,” Solid-State Electron., vol. 31, no. 10, pp. 1513–1532, 1988.

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[22] , “An investigation of the drive circuit requirements for the powerinsulated gate bipolar transistor (IGBT),” IEEE Trans. Power Electron.,vol. 6, pp. 208–219, Mar. 1991.

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[27] A. Ammous, B. Allard, and H. Morel, “Transient temperature measure-ments and modeling of IGBT’s under short-circuit,” IEEE Trans. PowerElectron., vol. 13, pp. 12–25, Jan. 1998.

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[30] J. D. Chatelain, Dispositifs à semiconducteur. Paris, France: Im-primerie Gautier-Villars, 1985, p. 321.

Anis Ammous was born in Sfax, Tunisia, in 1970.He received the electrical engineering degree fromthe Ecole National d’Ingenieur de Sfax (ENIS), in1994, and the Ph.D. degree in electrical engineeringfrom the Institut National des Sciences Appliquées(INSA), Lyon, France, in 1998.

In 1999, he joined the ENIS, where he is anAssistant Professor. His current research interestsare power semiconductor device modeling, theelectrothermal modelization and power electronicapplications to electrical vehicles.

Kaiçar Ammous was born in Sfax, Tunisia, in 1975.He received the electrical engineering degree fromthe Ecole Nationale d’Ingénieurs de Sfax (ENIS), in1997 and is currently pursuing the Ph.D. degree inelectrical engineering at the Institut National des Sci-ences Appliquées (INSA), Lyon, France.

His current research interests are averaged mod-eling of power converter, and the analysis of measure-ment errors in estimation of power switching lossesbased on electrical measurements.


Hervé Morel was born in Reims, France, in 1959.He received the engineer and Ph.D. degrees from theEcole Centrale de Lyon, France, in 1982 and 1985,respectively.

He is currently a Researcher at the Centre Nationalde la Recherche Scientifique (CNRS), Centre deGénie Electrique de Lyon (CEGELY), France. Heteaches basic electrical engineering. He managesthe research team on “power semiconductor devicesfor power electronics.” His research interestsare, semiconductor device characterizations and

modeling, converter simulations, and designs. A special interest exists for themodeling based on bond graphs.

Dr. Morel is member of the Society for Computer Simulation.

Bruno Allard (M’92) was born in Carignan, France,in 1965. He received the electrical engineering,M.Sc., and Ph.D. degrees from the Institut Nationaldes Sciences Appliquées (INSA), Lyon, France, in1988, 1989, and 1992, respectively.

Since 1991, he has been with the Centre de GénieElectrique de Lyon (CEGELY), France. He is anAssistant Professor at the Electrical EngineeringDepartment, INSA. His present research interestsinclude power semiconductor device modeling andpower electronic system simulation, both based on

the bond graph approach. In particular, he works on electro-thermal modelingand (integrated) system design.

Dr. Allard is a Member of the European Power Electronic Society and theEuropean Working Group of the IEEE Industrial Application Society.

Dominique Bergogne was born in Marvejols,France, in 1966. He received the Ph.D. degree inpower electronics from the Blaise Pascal University,Clermond-Ferrand, France in 1992.

He is currently an Associate Professor in elec-tronics at the IUT Institute, Saint-Etienne, France,where he teaches practical electronics. He is withthe Centre de Génie Electrique de Lyon (CEGELY)in the power device team. His research interest isdynamic electrothermal issues and power converter.He is implied in industrial partnerships.

Fayçal Sellami was born in Sfax, Tunisia, in 1956. He received the electricalengineering degree from the Faculté de Sciences et Techniques, Sfax, Tunisia, in1981, the “Docteur Ingénieur” (Ph.D.) degree and the “Doctorat d’Etat” degreein electrical engineering from the Institut National Polytechnique de Toulouse(INPT), France, in 1983 and 1986, respectively.

He is currently a Professor at the Ecole Nationale d’Ingénieurs de Sfax(ENIS), Sfax, Tunisia. His research interest is power electronics and he is theresponsible of the Power Electronic Laboratory (LEP) and the electric vehicleproject at the ENIS.

Jean Pierre Chante (M’81) was born in Lyon,France, in 1942. He received the “Doctorat d’Etat”degree from the University of Lyon, in 1981.

From 1980 to 1986, he managed a research teamin the field of power semiconductor devices at theEcole Centrale de Lyon. Since 1986, he has been aProfessor of Electronic Components and AppliedElectronics at the Institut National des SciencesAppliquées (INSA), Lyon, where he is the head ofthe Power Devices and Applications team whichis part of the CEGELY. He is also in charge of the

Centre Inter-Universitaire de Microélectronique de la Région de Lyon, whichis a regional research center in the microelectronic field. His interests are inhigh-temperature electronics, SiC-base components, advanced power devices,and CAD tools for power electronics.

Electrothermal modeling of IGBT’s: Application to short ...

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