[PPT] - Modeli ing ng and analysis of RF LDMOS for reliability issues and PowerPoint Presentation

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Model Modeli ing ng and analysis of RF LDMOS for reliability issues and analysis of RF LDMOS for reliability issues Electronic Microtechnology & Instrumentation Laboratory

M. Gares, M. A. Belaid, H. Maanane, M. Masmoudi, J. Marcon,
K. Mourgues and Ph. Eudeline

MOS AK WORKSHOP Boeblingen, March 24, 2006

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Presentation outline Presentation outline

► ►

Context Context of

f this study

this study

► ►

Objectives Objectives

► ►

Innovative reliability Innovative reliability bench bench

► ►

DC and CV characterization DC and CV characterization

► ►

RF LDMOS RF LDMOS modeling modeling

► ► Conclusion & prospects

Conclusion & prospects

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Context Context of

f this study

this study

Reliability improvement Reliability improvement of amplifier stages for S

f amplifier stages for S Band

Band radar (2 radar (2-

4

4 GHz GHz) )

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Presentation outline Presentation outline

► ►

Context Context of

f this study

this study

► ►

Objectives Objectives

► ►

Innovative reliability Innovative reliability bench bench

► ►

DC and CV characterization DC and CV characterization

► ►

RF LDMOS RF LDMOS modeling modeling

► ► Conclusion & prospects

Conclusion & prospects

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Objectives (1) Objectives (1) Objectives (1)

Characterization and

Characterization and modeling modeling for reliability issues for reliability issues

Obtaining

a set

f

significant parameters Obtaining a set

f

significant parameters such as such as t transconductance ransconductance (G (GM

M)

), threshold voltage , threshold voltage (V (VTH

TH)

), , O On n-

state resistance

state resistance (R (RON

ON)

) and capacitances and capacitances (C (CRSS

RSS, C

, COSS

OSS,

,… …). ).

Correlation between RF LDMOS electrical parameter drifts

Correlation between RF LDMOS electrical parameter drifts and any kind of degradation phenomenon, after RF Life and any kind of degradation phenomenon, after RF Life-

tests

tests ( (S S band band radar operating conditions). radar operating conditions). Electro-thermal modeling as a tool for RF LDMOS reliability study

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Objectives (2) Objectives (2)

What is the What is the Failure Failure mechanism mechanism involved involved? ?

Innovative Innovative Reliability Reliability bench bench

I I-

V and C

V and C-

V

V characterization characterization I I-

V and C

V and C-

V

V characterization characterization Mode Model ling ing after after RF Life RF Life-

tests

tests RF performances RF performances tracking tracking Modeling Modeling before before RF Life RF Life-

tests

tests

A set of significant A set of significant parameters parameters

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Presentation outline Presentation outline

► ►

Context Context of

f this study

this study

► ►

Objectives Objectives

► ►

Innovative reliability Innovative reliability bench bench

► ►

DC and CV characterization DC and CV characterization

► ►

RF LDMOS RF LDMOS modeling modeling

► ► Conclusion & prospects

Conclusion & prospects

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Computer+BILT PREF Tuner 40 dB attenuator

DUT

POUT

Att

X 8

Switchs RF 8 > 1 20dB attenuator 30 dB coupler Switchs RF 8 > 1 80 W amplifier Modulator RF Source Peak power meter Circulator Average Power Meter PIN

Innovative reliability Innovative reliability bench (1) bench (1)

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Innovative reliability bench (2) Innovative reliability Innovative reliability bench (2) bench (2)

A

A microwave microwave part part

A control/command part

A control/command part piloted piloted by a by a dedicated dedicated software software

Thermal module for

Thermal module for each devices each devices

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Presentation outline Presentation outline

► ►

Context Context of

f this study

this study

► ►

Objectives Objectives

► ►

Innovative reliability Innovative reliability bench bench

► ►

DC and CV characterization DC and CV characterization

► ►

RF LDMOS RF LDMOS modeling modeling

► ► Conclusion & prospects

Conclusion & prospects

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DC DC Characterization Characterization (1) (1)

DC DC mesurement setup mesurement setup

BILT ICCAP

Peltier module

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Measured Measured I IDS

DS-

V

VDS

DS characteristics

characteristics Measured Measured I IDS

DS-

V

VGS

GS characteristics

characteristics Data management Data management Extraplated Extraplated I IDS

DS-

V

VGS

GS characteristics

characteristics Consistency Consistency

f Data
f Data

Measured Measured (symbols) (symbols) and and extrapol extrapolated ated ( (continuous lines continuous lines) ) output

utput characteristics

characteristics Measured Measured (symbols) (symbols) and extrapolated and extrapolated ( (continuous lines continuous lines) ) transfer characteristics transfer characteristics

V VDS

DS=0

=0… …26 V 26 V with with a a step step of

f 520 mV

520 mV V VGS

GS=3.5

=3.5… …5.8 V 5.8 V with with a a step step of

f 383 mV

383 mV V VDS

DS=0

=0… …26 V 26 V with with a a step step of

f 4.33 V

4.33 V V VGS

GS=3.5

=3.5… …5.8 V 5.8 V with with a a step step of

f 45 mV

45 mV

DC DC Characterization Characterization (2) (2)

R Results esults & & Measurement consistency Measurement consistency

5 10 15 20 25 100 200 300 400 500

IDS [mA] VDS [V]

3,5 4,0 4,5 5,0 5,5 6,0 100 200 300 400 500

IDS [mA] VGS [V]

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RF LDMOS RF LDMOS device device cross cross-

section

section with its with its intrinsic intrinsic capacitances capacitances

CV CV Characterizatio Characterization (1) n (1)

localization localization of capacitances

f capacitances

N+ N+ Source Gate Drain

x y

N-LDD P

+

sinker P

body

CGS CGD CDS

N+ N+ Source Gate Drain

P+ Substrate x y x y

N-LDD P

+

sinker P

body

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Measured Measured C CRSS

RSS, C

, CISS

ISS and

and C COSS

OSS ,

, Fr Fre eq=1MHz q=1MHz and and V VDS

DS=[0V, 30V]

=[0V, 30V] at at room room temperature temperature

C CV V Characterization Characterization (2) (2)

Primary Primary capacitance capacitance measurements measurements

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Measured Measured C CGS

GS vs.

vs.V VGS

GS profile

profile (V (VDS

DS= 0V

= 0V and and Fr Fre eq.=1 MHz) q.=1 MHz) at at room room temperature temperature. .

CV CV Characterization Characterization (3) (3)

Intrinsic Intrinsic capacitance capacitance measurements measurements

6
4
2

2 4 6 8 8 9 10 11 12 13 14 15 16 Measured CGS vs. VGS

CGS [pF] VGS [V]

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Presentation outline Presentation outline

► ►

Context Context of

f this study

this study

► ►

Objectives Objectives

► ►

Innovative reliability Innovative reliability bench bench

► ►

DC and CV characterization DC and CV characterization

► ►

RF LDMOS RF LDMOS modeling modeling

► ► Conclusion & prospects

Conclusion & prospects

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An

An empirical empirical large signal non large signal non-

linear

linear model. model.

An

An electro electro thermal model thermal model including static and dynamic including static and dynamic thermal thermal dependencies dependencies. .

An

An electro electro thermal model, thermal model, taking into account taking into account self self heating heating effects and temperature effects and temperature influence on LDMOS influence on LDMOS electric electric behaviour. behaviour.

RF LDMOS RF LDMOS modeling modeling

Improved Improved MET LDMOS MET LDMOS Model Model overview

verview

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S D G

Cgd Lg Ls Rs Cgs Cds Ids + Vds Ld Rd Rg Ri Rsub Rgd Cth_CP Rth_CP Pdiss Ta +

+

∆T Cth_PH Rth_PH Cth_HA Rth_HA

Electric

model Thermal model

RF RF LDMOS LDMOS modeling modeling

Improved Improved MET LDMO MET LDMOS Model S Model overview

verview

Large signal Large signal equivalent equivalent circuit of circuit of the the MET LDMOS model MET LDMOS model

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RF LDMOS RF LDMOS modeling modeling

Improved Improved MET LDMOS model MET LDMOS model overview

verview (thermal aspects)

(thermal aspects)

H e a tF lo w C h ip P a c k a g e H e a ts in k A m b ie n ta ir

C

th _ C P

R

th _ C P

C

th _ P H

R

th _ P H

C

th _ H A

R

th _ H A

T

A

T

H

T

P

T

C

th _ C A

R

th _C A

a diss CA th

T P R T + ⋅ = ∆

_

ds ds diss

V I P ⋅ =

HA th PH th CP th CA th

R R R R

_ _ _ _

+ + =

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An ADS "SDD" (

An ADS "SDD" (Symbolic defined device Symbolic defined device) ) was developed was developed. .

The

The SDD SDD is a feature in ADS, which allows the user to specify is a feature in ADS, which allows the user to specify a real a real-

time model description, without compilation.

time model description, without compilation.

The developed

The developed SDD SDD covers the transistor DC covers the transistor DC forward forward current current id=f( id=f(vGS vGS, ,vDS vDS), the series resistors RG, RS and RD, as well as the ), the series resistors RG, RS and RD, as well as the charges charges qGS qGS, , qGD qGD and and qDS qDS. .

The thermal network is implemented taking into consideration

The thermal network is implemented taking into consideration the temperature dependence of the parameters. the temperature dependence of the parameters.

RF LDMOS RF LDMOS modeling modeling

Implementing the model equations into IC Implementing the model equations into IC-

CAP’s

CAP’s ADS ADS circuit page circuit page

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RF LDMOS RF LDMOS modeling modeling

Main Main parameters parameters of

f the

the model model

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Measured Measured transfer transfer characteristics characteristics (log( (log(I IDS

DS )

) vs.V vs.VG

GS S)

) with the with the influence of few MET LDMOS model influence of few MET LDMOS model parameters parameters Measured Measured ( (symbols symbols) ) and modelled and modelled ( (continuous lines continuous lines) ) transfer characteristics transfer characteristics, , with with V VGS

GS=3.8

=3.8-

5.8 V

5.8 V ( (step step=56 mV) =56 mV) and and V VDS

DS=5.2 V, 17.68 V

=5.2 V, 17.68 V & & 26 V 26 V

RF LDMOS RF LDMOS modeling modeling

Sub Sub-

threshold modeling

threshold modeling : : log(I log(IDS

DS) vs. V

) vs. VGS

GS

3,5 4,0 4,5 5,0 5,5 6,0 1E-3 0,01 0,1 1

measured log(IDS) vs. VGS modelled log(IDS) vs. VGS

IDS [A] VGS [V]

2,0 2,5 3,0 3,5 4,0 4,5 5,0 5,5 6,0 1E-9 1E-8 1E-7 1E-6 1E-5 1E-4 1E-3 0,01 0,1 1 Log(IDS) vs. VGS, with VDS=22,5V

IDS [A] VGS [V]

VTH VST BETA=GM

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RF LDMOS RF LDMOS modeling modeling

Transfer characterictics modeling Transfer characterictics modeling (I (IDS

DS vs. V

vs. VGS

GS)

)

Measured Measured ( (symbols symbols) ) and modelled and modelled ( (continuous continuous lines lines) ) transfer transfer characteristics characteristics, , with with V VGS

GS=3.8 V

=3.8 V-

5.8 V (

5.8 V (step step=56 mV) =56 mV) and and V VDS

DS=5.2 V, 17.68 V

=5.2 V, 17.68 V & & 26 V. 26 V.

4,0 4,5 5,0 5,5 6,0 100 200 300 400 500 Measured IDS vs. VGS Modelled IDS vs. VGS

IDS [mA] VGS [V]

3,5 4,0 4,5 5,0 5,5 6,0 100 200 300 400 500 600

IDS [mA] VGS [V]

BETA=GM

hmic Effect s RS, VK

VGEXP, DELTA VDS dependency : GAMMA, LAMBDA Measured Measured transfer transfer characteristics characteristics I IDS

DS vs.V

vs.VG

GS S with

with the the influence of few MET LDMOS model influence of few MET LDMOS model parameters parameters

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Measured Measured ( (symbols symbols) ) and modelled and modelled ( (continuous lines continuous lines) output ) output characteristics characteristics with with V VDS

DS=0

=0-

26 V (

26 V (step step= =520 mV) 520 mV) and and V VGS

GS=4.45 V, 4.9 V, 5.35 V

=4.45 V, 4.9 V, 5.35 V & & 5.8 V 5.8 V

5 10 15 20 25 100 200 300 400 500 600 measured IDS vs. VDS modelled IDS vs. VDS

IDS [mA] VDS [V]

5 10 15 20 25 100 200 300 400 500

IDS [mA] VDS [V]

ALPHA, RD GAMMA VBR, K1, K2 LAMBDA BETA=GM

RF LDMOS RF LDMOS modeling modeling

Output Output characteristics modeling characteristics modeling : : I IDS

DS vs. V

vs. VDS

DS

Measured Measured output

utput characteristics

characteristics ( (I IDS

DS vs. V

vs. VDS

DS)

) with the with the influence of few MET LDMOS model influence of few MET LDMOS model parameters parameters

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Summary Summary of few DC

f few DC significant parameters extrapolated

significant parameters extrapolated by by modeling modeling

RF LDMOS RF LDMOS modeling modeling

Model Model parameter parameter extraction extraction

V S V Ohms

values obtained by modeling (Fitting error <1%) MET model parameters Classic DC parameter names

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CGS1 CGS1

CGS2*(1+ CGS2*(1+tanh tanh(CGS6*( (CGS6*(vGS vGS+CGS3))) +CGS3))) CGS4*(1 CGS4*(1-

tanh

tanh( (vGS vGS*CGS5)) *CGS5)) CGS1+CGS2*(1+ CGS1+CGS2*(1+tanh tanh(CGS6*( (CGS6*(vGS vGS+CGS3)))+CGS4*(1 +CGS3)))+CGS4*(1-

tanh

tanh( (vGS vGS*CGS5)) *CGS5))

RF LDMOS RF LDMOS modeling modeling

C CG

GS S capacitance

capacitance modeling modeling

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Measured Measured ( (symbols symbols) ) and modelled and modelled ( (continuous lines continuous lines) ) C CGS

GS capacitance,

capacitance, V VGS

GS= [

= [-

5 V,7 V]

5 V,7 V] and and V VDS

DS= 0 V,

= 0 V, with Freq with Freq= =1 MHz. 1 MHz. Measured Measured ( (symbols symbols) ) and modelled and modelled ( (continuous continuous lines lines) ) C CISS

ISS, C

, COSS

OSS &

& C CRSS

RSS capacitances,

capacitances, V VDS

DS=[0 V,26 V]

=[0 V,26 V], , V VGS

GS=0V,

=0V, and Freq and Freq= =1 MHz. 1 MHz.

4 8 12 16 20 24 1E-13 1E-12 1E-11 1E-10

Measured CISS vs. VDS Modelled CISS vs. VDS Measured COSS vs. VDS Modelled COSS vs. VDS Measured CRSS vs. VDS Modelled CRSS vs. VDS

C [F] VDS[V]

RF LDMOS RF LDMOS modeling modeling

CV CV modeling results

modeling results

6
4
2

2 4 6 8 8 9 10 11 12 13 14 15 16 measured CGS vs. VGS modelled CGS vs. VGS

CGS [pF] VGS [V]

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RF LDMOS RF LDMOS modeling modeling

Thermal simulation Thermal simulation results results

5 10 15 20 25 30 10 20 30 40 50 60 70 80

VGS=5.40 V VGS=5.06 V VGS=4.72 V VGS=4.38 V VGS=4.04 V

T [°C] VDS [V]

Temperature

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Presentation outline Presentation outline

► ►

Context Context of

f this study

this study

► ►

Objectives Objectives

► ►

Innovative reliability Innovative reliability bench bench

► ►

DC and CV characterization DC and CV characterization

► ►

RF LDMOS RF LDMOS modeling modeling

► ► Conclusion & prospects

Conclusion & prospects

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Conclusion Conclusion

An

An improved improved MET LDMOS model ( MET LDMOS model (three three thermal thermal cells cells), ), taking taking into account into account self self-

heating effects and the temperature

heating effects and the temperature influence influence was developped was developped. .

The

The DC DC and and CV CV modeling modeling results fitted well with those obtained results fitted well with those obtained from the measurements from the measurements

A

set

f

A set

f

significant parameters significant parameters has been has been extrapolated extrapolated by by modeling and used modeling and used to help to help identifying identifying a a degradation degradation phenomenon phenomenon after after RF life RF life-

tests.

tests.

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Prospects Prospects

S

S parameter measurements and parameter measurements and simulations are in simulations are in progress progress, to , to get get a a complete complete compact model compact model and and have a large have a large significant significant parameter parameter set. set.

Simulation in

Simulation in Harmonic Harmonic Balance (P Balance (POUT

OUT vs. P

vs. PIN

IN, IMD,

, IMD, … …) for RF ) for RF LDMOS performance LDMOS performance predictions after predictions after RF life RF life-

tests.

tests.

Channel

Channel temperature measurement temperature measurement in in order

rder to

to confirm the confirm the thermal model. thermal model.

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Questions Questions

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RF Life RF Life-

test conditions (1)

test conditions (1)

DC

DC

V VDS

DS=44 V,

=44 V, V VGS

GS=3,79 V

=3,79 V with with I IDQ

DQ=3mA

=3mA at at 25°C. 25°C. Fréq Fréq= 2,9 = 2,9 GHz GHz. . Pulse Pulse length length/ /duty duty cycle=500 µs/50%. cycle=500 µs/50%. P PIN

IN=30,5 dBm, P

=30,5 dBm, POUT

OUT=43

=43-

44 dBm.

44 dBm.

RF

RF

Thermal

Thermal

T (°C) = 10, 80,110 et 150°C. T (°C) = 10, 80,110 et 150°C.

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RF Life RF Life-

test conditions

test conditions (2)

(2)

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Results obtained after Results obtained after RF Life

RF Life-

test

test

RF RF saturated saturated output power

utput power evolution over

evolution over ageing ageing time (1500h) for time (1500h) for various various temperature temperature conditions. conditions. Drain source Drain source current evolution over ageing current evolution over ageing time (1500h) for time (1500h) for various temperature various temperature conditions. conditions.

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RF LDMOS RF LDMOS modeling modeling

Thermal aspects Thermal aspects

G D S

Drift region: Hot spots

1 2 3 4 5 6 7 8 1 9 8 7 6 5 4 3 2 1