gan on sic - rfmw ltd. · first wafer fab’ed darpa wide bandgap program major research program...

QorvoTM Confidential & Proprietary Information © 2015 Qorvo, Inc.

 1 QorvoTM Confidential & Proprietary Information © 2015 Qorvo, Inc.

GaN on SiC 15 Years of Reliability & Producibility

RFMW is the Premier Pure Play Technical Distributor of RF & Microwave Components

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RF Specialists in a Broadline World

Qorvo Gateway – Your One-‐Stop-‐Shop As the distributor for both RFMD and TriQuint products, RFMW is uniquely posi=oned to support your Qorvo device needs. Our web site includes links to product specifica=ons, data sheets and applica=on notes. You can easily request samples and evalua=on boards on many of the Qorvo products with just a few clicks. RFMW is your one-‐stop-‐shop for Qorvo GaN and other fine Qorvo devices. Visit: www.rfmw.com/Qorvo


 5

The Promise

Semi-Ionic Crystal

•  Large Bad Gap •  High Electric Fields

High Fields

•  High Power Densities •  Small Devices

Small Devices

•  High Bandwidth •  High Efficiency •  High Power •  High Gain

1999: GaN, A New Enabling Technology for RF Applications


 6

Qorvo's Long Heritage with GaN on SiC

>7,000 wafers processed since the first release in 2008

1999 2002 2004 2008 2011 2012

First wafer fab’ed

DARPA wide bandgap program

Major research program award

Released 0.25um QGaN25 process on

75mm wafers

Release 0.25um QGaN25 process on 100mm wafers

Major A&D design win

2013

Release 0.25um HV and 0.15um processes

>17,000 devices life tested with >1M hours of

accumulated stress time

>15,000 devices in phased array operational test, with >4M device

hours and no failures

2014

MRL 9

2015

Release 0.5um QGaN50 and QGaN50-HV process

Commercial design wins


 7

Today 2015: GaN Technologies at Qorvo

Jul 2013

Dec 2014

Apr 2013

QGaN09

QGaN25-HV

2.0W/mm

3.0W/mm

6.0W/mm

7.0W/mm

9.0W/mm QGaN50

Oct 2012 QGaN25

QGaN15

FT a

t O

pe

rati

on

Fre

qu

en

cy (

GH

z)

Operation Voltage (V)

To be released in 2016


 8

The Pillars of a Success Story

Performance

Reliability Producibility


 9

Today 2015: GaN Technologies at Qorvo

QGaN15 QGaN25 Gen II QGaN25-HV QGaN50

Op. Voltage 20V 40V 48V 65V

POut 3.0W/mm 6.0W/mm 7.0W/mm 9.0W/mm

PAE 50% 60% 78% 80%

Gain 9dB (35GHz) 13dB (10GHz) 21dB (3.5GHz) 19dB (2.17GHz)

FTMax > 65GHz >35GHz 25GHz 18GHz

FMax >150GHz >150GHz >150GHz >150GHz

MTTF (200C) >107h (at 22V) >107h (at 40V) >107h (at 48V) >107h (at 65V)

QGaN15 targets wide bandwidth microwave and Ka-band products, QGaN25 Gen II targets X and Ku-band products, QGaN25-HV targets L- and S-band products, and QGaN50 targets UHF to C-band frequencies with high harmonic capabilities and thus extra high efficiencies


 10

Performance




 11

Case Study: QGaN25

Oct 2012

(9.0W/mm)

QGaN15 QGaN25 QGaN25-HV QGaN50

Op. Voltage 20V 40V 48V 65V

POut 3.0W/mm 6.0W/mm 7.0W/mm 9.0W/mm

PAE 50% 60% 78% 80%

Gain 9dB (35GHz) 13dB (10GHz) 21dB (3.5GHz) 19dB (2.2GHz)

FTMax > 65GHz >35GHz 25GHz 18GHz

FMax >150GHz >150GHz >150GHz >150GHz

MTTF (200C) >107h (at 22V) >107h (at 40V) >107h (at 48V) >107h (at 65V)

(3.0W/mm)

(5.5W/mm) TQGaN25

TQGaN09

TQGaN50

Fre

qu

en

cy o

f O

pe

rati

on

(G

Hz)

Operation Voltage (V)

TQGaN15 TQPHT25

TQPHT15

TQPHT35HV

TQPHT70HV/HBT

(2.0W/mm)

0.15um mHEMT


 12

DC performance and producibility over hundreds of wafers Case Study: QGaN25

Intrawafer spread: median spread (standard deviation) of all the wafer spreads Interwafer spread: spread (standard deviation) of all the wafer medians

Parameter QGaN25

IDMax (Average, sinter, sintra) 1035mA/mm, 2.34%, 1.01%

CC (Average, sinter, sintra) 0.975, 0.65%, 0.38%

GM (Average, sinter, sintra) 271.0mS/mm, 3.50%, 1.42%

BV (Average, sinter, sintra) 171V, 10.99%, 4.99%

VP1 (Average, sinter, sintra) -2.962V, 0.189V, 0.097V

Log IG (Average, sinter, sintra) -1.42 log(mA/mm), 0.67 log(mA/mm), 0.52 log(mA/mm)

Drift (Average, sinter, sintra) 0.90 mA/mmDec, 0.39mA/mmDec, 0.31mA/mmDec


 13

SFC performance and producibility over hundreds of wafers Case Study: QGaN25


Parameter Condition QGaN25

FT2 (Average, sinter, sintra) 40V, 50mA/mm 21.6GHz, 5.24%, 3.88%

FMax (Average, sinter, sintra) 40V, 50mA/mm 166.4GHz, 7.31%, 4.55%

GMM (Average, sinter, sintra) 40V, 50mA/mm 205.5mS/mm, 7.82%, 5.51%

CGS (Average, sinter, sintra) 40V, 50mA/mm 1.454pF/mm, 5.01%, 2.83%

CDS (Average, sinter, sintra) 40V, 50mA/mm 229.4fF/mm, 4.42%, 2.21%

CDG (Average, sinter, sintra) 40V, 50mA/mm 36.1fF/mm, 4.54%, 3.13%

RDS (Average, sinter, sintra) 40V, 50mA/mm 297.4Wmm, 10.52%, 6.01%


 14

A comparison among GaN technologies Technology Maturity, Producibility


DC Spread

4x100um QGaN15 QGaN25 QGaN25HV QGaN50 IMax 1.72%, 1.34% 2.34%, 1.01% 1.87%, 1.44% 0.99%, 1.16% CC 0.83%, 0.77% 0.65%, 0.38% 0.40%, 0.31% 0.20%, 0.20% GM 3.81%, 2.02% 3.50%, 1.42% 2.73%, 2.33% 1.55%, 1.70% VP 389mV, 326mV 189mV, 97mV 92mV, 85mV 60mV, 50mV

4x100um QGaN15 QGaN25 QGaN25HV QGaN50 FT 7.09%, 4.67% 5.24%, 3.88% 1.90%, 1.94% 1.19%, 3.09%

GMM 11.2%, 6.50% 7.82%, 5.51% 3.14%, 2.14% 1.23%, 4.99% CGS 5.01%, 2.83% 5.01%, 2.83% 2.23%, 1.40% 2.14%, 2.37% CGD 814%, 2.82% 4.54%, 3.13% 3.88%, 3.28% 1.94%, 2.51% CDS 3.33%, 1.55% 4.42%, 2.21% 3.77%, 2.97% 2.43%, 2.52%

RF Spread


 15

A comparison between GaN and GaAs producibility Technology Maturity, Producibility

DC Spread

GaAs GaN

QPHT15 QPHT35HV QGaN25 Gen II

FT (σinter, σintra) 4.45%, 1.40% 4.59%, 1.87% 5.08%, 4.03%

GMM (σinter, σintra) 3.99%, 2.64% 5.65%, 1.73% 8.47%, 6.11%

CGS (σinter, σintra) 4.94%, 2.80% 6.14%, 2.84% 5.50%, 3.06%

CDS (σinter, σintra) 5.38%, 3.39% 5.64%, 2.53% 4.54%, 2.21%

CGD(σinter, σintra) 3.79%, 1.94% 7.57%, 3.39% 4.61%, 3.09%

GaAs GaN

QPHT15 QPHT35HV QGaN25 Gen II

IMax (σinter, σintra) 2.16%, 1.15% 5.02%, 1.56% 1.78%, 1.37%

GM (σinter, σintra) 2.19%, 0.85% 6.72%, 1.84% 1.96%, 1.22%

Vp (σinter, σintra) 48mV, 20mV 49mV, 16mV 120mV, 90mV

BV (σinter, σintra) 4.96%, 2.99% 6.55%, 3.89% 11.10%,5.44%

Log_IG (σinter, σintra) 0.304, 0.149 0.309, 0.086 0.449, 0.333

RF Spread


 16

Technology Maturity, Producibility

GaN and GaAs are at the same level of producibility both at the

material and process level


 17


Performance



 18

Inverse piezoelectric model, (MIT) 2005 GaN Reliability and Physics of Failure

Initial model: electric field induced defect formation through inverse piezoelectric effect in the AlGaN barrier

1. High VDG results in high field in the drain gate edge region

3. Piezoelectric strain adds on top of lattice mismatch strain

4. If excessive, strain relaxes during operation through crystallographic defect formation

5. Defects are electrically active and behave as electron traps

2. Through inverse piezoelectric effect, high field introduces severe strain in the AlGaN barrier

Proposed by Joh and del Alamo at MIT

Source FP1

Gate FP2


 19

First evidence of mechanical degradation, TriQuint November 2006 GaN Reliability and Physics of Failure

0 100 200 300 400 500 600 -5

-4

-3

-2

-1

0 P

Ou

t D

eg

rad

atio

n (

dB

)

Time (h)

RF LifeTest. 28V, 280C Fresh

Degraded

Mechanical deformation on the drain edge of the gate consistent with inverse piezoelectric theory


 20

Improved degradation model, TriQuint June 2009 GaN Reliability and Physics of Failure

•  The dynamics of the mechanical degradation and the role of the surface initiating it are the keys for explaining the temperature acceleration of the degradation and the intra and interwafer reliability spread

1. Chemical pitting of the GaN surface ‏

3. Propagation of the cracking along the gate width

2. µCracking of the AlGaN barrier through inverse piezoelectric effect

6

1

disfiguration=4: crack with 0 to 4 nm deep pit

4 5

2 0


 21

Improved degradation model verification, (MIT) January 2010 GaN Reliability and Physics of Failure

Deformation starts through surface pitting presence. Experiment rules out dislocation effects.

MIT: Joh and del Alamo

Degradation Evolution vs. Time

0 0.2 0.4 0.6-2.5

-2

-1.5

-1

-0.5

0

0.5

x (µm)

Avera

ge Pi

t Dep

th (nm

)

200 nm 0V

20V

15V

42V

57V

Degradation Evolution vs. Voltage Stress


 22

Efforts GaN Reliability Improvements

Strain Engineering (Epi/Process)

Encapsulation (Process)

Surface Engineering

(Substrate/Epi/Process)


 23

Median failure time GaN Reliability Results, Case Study: QGaN50

IDM

ax

De

gra

dat

ion

(%

)

Time(h)

A very reliable technology

355C 385C 415C


 24

All GaN technologies Technology Level Reliability Assessment

DC RELIABILITY AT MAXIMUM OPERATION VOLTAGE

•  3 temperatures

•  Degradation criteria: 10% IDMax drop

•  Burn in: none

•  Selected lots

DC RELIABILITY SCREEN

•  Single temperature



•  All wafers


 25

3T reliability Reliability Assessment, Case Study: QGaN25

•  Sampled (2 lots. 144 devices)

•  40V, 250mA/mm




 26

3T LifeTest, failure distribution Reliability Assessment, Case Study: QGaN25

3T material LifeTest of 2 wafers showing activation energy of 2.15eV and lognormals of 1.34

Confidence Level EA (eV)

50% 2.15

70% 2.06

90% 1.94

QGaN25-Failure Distribution

Time to Failure (h)

Cu

mu

lati

ve F

ailu

re (

%) Lognormal


 27

Arrhenius plot (50%) Reliability Assessment, Case Study: QGaN25

At 50% confidence level, MTTF ~ 7.3 107 hours at 200C

QGaN25 Arrhenius Plot

Me

dia

n T

ime

to

Fa

ilure

(h

)

Temperature (C)


 28

Reliability evaluation at 200C Reliability Assessment, Case Study: QGaN25

Good survivability at 200C

Survivability

200C MTTF t10% t5% t1%

50% Confidence 8360 years 1499 years 921 years 369 years



200C 104 h 105h 106h

50% Confidence >99.99% >99.99% 99.93%

70% Confidence >99.99% >99.99% 99.75%

90% Confidence >99.99% >99.99% 98.78%

Cumulative Failure


 29

Reliability screen Reliability Assessment, Case Study: QGaN25

•  All delivered wafers going through a reliability screen

•  40V, 250mA/mm, 355C channel temperature

•  30h (~1M at 200C)




 30

Screen 40V, 250mA/mm, 355C, 30h Reliability Assessment, Case Study: QGaN25

Wafers

QGaN25 332/333

Passing. Reliability Screen. Wafers

Devices

QGaN25 1887/1943

Passing. Reliability Screen. Devices

Population: 333 wafers from 120 lots


 31

Distribution at 355C, 40V, 250mA/mm Reliability Assessment, Case Study: QGaN25

Cu

mu

lati

ve F

ailu

re (

%)

GaN25 Gen II. All Wafers Lognormal – 90% LB

Time (h)


 32

Arrhenius plot for 5% failures (50% confidence) Reliability Assessment, Case Study: QGaN25

t5 (

%)

Arrhenius Plot. All GaN25 Gen II Wafers Lognormal

Temperature (C)

At 50% activation energy confidence level, 5% failures ~ 3.0 107 hours at 200C

360340320300280260240220200

100000000

10000000

1000000

100000

10000

1000

100

Temperature (C)

t5%

(h

)

Arrhenius Plot. All Gan25 Gen II WafersLognormal


 33

Reliability quantification assuming activation energy at 50%, 70% and 90% confidence

Reliability Assessment, Case Study: QGaN25

200C t10% t5% t1%

50% 12488 years 3666 years 368 years

70% 7419 years 2178 years 219 years

90% 3523 years 1034 years 103.8 years

200C 104h 105h 106h

50% >99.99% 99.96% 99.62%

70% >99.99% 99.93% 99.41%

90% 99.99% 99.86% 98.92%


 34

Catastrophic failure (40V, 250mA/mm. 355C) Reliability Assessment, Case Study: QGaN25

Three catastrophic failures after more than 35556 device hours at 355C

Devices Catastrophic

Failures

MTBF (40V, 250mA/mm,355C)

GEN II 1943 3 35556 hours


 35

Reliability Assessment

GaN’s reliability is outstanding at 200C and we have the

statistics to prove it


 36

Connect with Qorvo Resources

•  Learn more about Qorvo’s GaN expertise

•  Visit our GaN webpage at www.qorvo.com/go/gan

•  Get your copy of our ‘GaN For Dummies®’ e-books at www.qorvo.com/go/gan-for-dummies

•  Download our GaN brochure at www.qorvo.com/go/gan-brochure

•  View our ‘GaN Thermal Analysis for High-Performance Systems’ white paper at www.qorvo.com/go/gan-white-paper

Thank You

gan on sic - rfmw ltd. · first wafer fab’ed darpa wide bandgap program major research program...

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