New GaN Platform enabling High-efficiency and Small-size High ...

GaN for Green Future

CONFIDENTIAL 1

New GaN Platform

enabling

High-efficiency and Small-size

High-power Electronic Systems

Yuanshan Advanced Material Technologies Inc.


CONFIDENTIAL 2

Established:Location:Capital: ¥200MEmployee :

Business: GaN epitaxial wafers, Developing GaN electronic devices

上海

October 2017Jining City, 272000 Shandong, China

50



CONFIDENTIAL 3

World first F100 mm GaN HEMT wafer

World first 600 [V] vertical GaN Shottky diode

Invention of Polarization Super-junction Transistor

World first 1,000 [V] switching

New vertical 8-inch multi-wafer MOCVD reactor

3,300 [V] GaN PSJ power transistor

10,000 [V] power transistor and 8,000 [V] Schottky diode

Developing GaN power modlues

Wind-turbine

Achievement

GaN MOCVD Reactor

52 mm

32 mm

HV LVOUT

1,650 V

GaN chip



CONFIDENTIAL 4

Contributes to the social infrastructure in 21st century

through developing/providing Gallium Nitride

(GaN) power electronic devices.

Commitment

GaN for green future

CONFIDENTIAL



CONFIDENTIAL 5

.5 1 2 3 105 20 30 50

Operating Voltage [ kV ]

50k

500k

200k

100k

1M

2M

5M

10M

20MO

utp

ut

Po

wer

[ W

]

GaN Application Arena

Power Grid

EV MotorWPTFast Charger

Natural Energy

Train MotorAir Conditioner

HV distributionConversion

Conven-tional GaN



CONFIDENTIAL 6

challenges the present giant, Si-IGBT (Insulated-Gate-Bipolar-Tr.)

Perf

orm

an

ce

( lo

w-l

oss, sp

eed

, vo

lum

e)

Cost [¥]

GaN-PSJ

MOS

SJ-MOS

SiC

Low-voltage

High-voltage

Hard challenge due to high cost

GaN

low cost & high performance

Medium-voltage

SiC diode

1,000 5,000500100 1e4

(15~20 A class Transistor )

IGBT

GaN/SiSiC


YUANSHAN


CONFIDENTIAL 7

10-9

10-8

10-7

10-6

10-5

10-4

0 2 4 6 8 10

off state

Dra

in C

urr

en

t [A

]

Drain Voltage [kV]

Vg : -10 V

Lpsj : 100 mmWg : 100 mm

today’s Achievement

D（排出）S（源）

G（扉）

VGS（扉電圧）

0

1

2

3

4

5

6

7

0 2 4 6 8 10

IdVd

Dra

in C

urr

en

t [A

]

Drain Voltage [V]

Vg : +2 V

0 V

-2 V

-4, -6 V

Lpsj : 100 mmWg : 100 mm

Ron :

805 m

D（排出）S（源）

G（扉）

VDS = 印加電圧

(I) GaN Transistor : Breakdown voltage > 10 kV



CONFIDENTIAL 8

(II) GaN Schottky diode : Breakdown voltage > 8 kV

10-9

10-8

10-7

10-6

10-5

0 2 4 6 8 10

Reverse I-V

An

od

e C

urr

en

t [A

]

Cathode Voltage [kV]

Lpsj : 100 mm

0

4

8

12

16

0 2 4 6 8 10 12 14

Forward I-V

An

od

e C

urr

en

t [A

]

Anode Voltage [V]

Ron : 717 m

Lpsj : 100 mm



CONFIDENTIAL 10

(II) GaN Schottky diode : Reverse Recovery characteristics

-5~18 VDouble Pulse

DUT

1m

H 1

.6 A

200 V

IGBT:ON

IGBT:OFF

Current Prob. Ir

H15R12031.2 kV 15 A

-5

-4

-3

-2

-1

0

1

2

-10 0 10 20 30 40

Reverse recovery characteristics

If [

A]

Time [ns]

GaN PSJ SBDTrr : 16.4 nsIrr : 4.1 A

SiC DiodeC2D10120Trr : 19.6 nsIrr : 4.2 A

Very fast, more efficient than SiC diode

Test circuit



CONFIDENTIAL

IGBT

GaN-FET

GaN FET : 1650 V / 5 A

(III) GaN FET : Comparison of switching-loss with IGBT

1,650 V

Double-pulse method

16501200900600

Input voltage [V]S

wit

ch

ing

lo

ss [m

J]



CONFIDENTIAL 12

(IV) 400V/800V DC/DC up-converter

400 V

800 V

1.25 A

800 V

-10 / +3 V

20ms



CONFIDENTIAL

(V) Intelligent power module

Half bridge

Input DC voltage : 1.2 [kV]Output current : 30 [A]Switching frequency : 500 [kHz]Power density : 2 [kW/cc]

Rear side

High side

Low side

HV

LV

OUT

Gate controller

GaN

GaN

52 mm

32 mm

HV LVOUT


Half bridge switching measurement

CurrentTon 10.3nSecToff 10.6nSec

VoltageTon 45.7nSecToff 8.53nSec

CH1:OutPut Current31.6A

CH3:OutPut Voltage789.9V

SW Losson 502uJoff 138uJ

500 kHz

Hi-Side

Lo-Side

800ns 800ns

2 uSec

CH3 0V

CH1 0AIsolator

FG

400uH

CH3:OutPut Voltage

CH1:OutPut Current

800 V

0 V

Power Supply

IPM




CONFIDENTIAL 15

Technology platform for GaN power equipment

Principal device mechanismLateral FET powered by Polarization Super-junction, (PSJ)

Epitaxy platformGaN-on-sapphire substrate

PackagingDirect connection to the circuit board

Thermal management technologyDirect touch on heat-sink



CONFIDENTIAL 16

Principal device mechanism( Conventional GaN FET vs. POWDEC’s GaN FET )

S D

AlGaN

GaN

G

Conventional structure POWDEC PSJ - structure

vs.Electron channel (2DEG)

on

Current-flow state

S D

AlGaN

GaN

G

off

E

Current-stop state

S

GaN

G

D

AlGaN

GaN

Hole presenton

S

GaN

G

DGaN

Hole disappeared

off

E E E E E

Current-flow state

Current-stop state



CONFIDENTIAL 17

Principal device mechanism

Ele

ctr

ic F

ield

(E

)

Conventional structure

S D

AlGaN

GaN

G

off

E

Reverse-mode

Epeak

Under the Current-off state

• Very strong electric field, Epeak appears in the Gate-edge.

• If Epeak > 3.3 [MV/cm], the device is destroyed.



CONFIDENTIAL 18

Principal device mechanism

Field plate (FP)

Ele

ctr

ic F

ield

(E

)

without FP

with FP

Decrease of peak electric field

Conventional structureReverse-mode

S D

AlGaN

GaN

G

E

Under the Current-off state

• The conventional approach of decreasing the Epeak is adding field-plates (FP) on the gate electrode.

• The FP splits the Field and decreases the Epeak, but not enough for high voltage applications.



CONFIDENTIAL 19

Field plate (FP)

Ele

ctr

ic F

ield

(E

)

without FP

with FP

Decrease of peak electric field

Conventional structure

vs.

Reverse-mode

S D

AlGaN

GaN

G

E

Principal device mechanismNew approach Polarization Super-junction,(PSJ)

POWDEC PSJ - structure

Ele

ctr

ic F

ield

(E

)

POWDEC PSJ - structure

Low & Flat Electric Field

S

GaN

G

DGaN

Hole evacuated

off

E E E E E

electron evacuated



CONFIDENTIAL 20

Epitaxy platform( Layer structure and deposition time)

~ 6 mm

GaN

AlGaN/GaN Buffer layer

Si (111) Sub.

AlN protection layer

AlGaNS DG

Sapphire sub.

GaN

AlGaNS D

G

1 mm

GaN-on-Si MOCVD GaN-on-sapphire MOCVD

LED compatible growth sequence.

The growth time is about 2 hours from loading to finish.

vs.



CONFIDENTIAL 21

Epitaxy platform(Influence of thermal expansion deference between GaN and substrate )

Si

GaN vs.

crackbow

GaN-on-Si MOCVD GaN-on-sapphire MOCVD

GaN

sapphire

tensile stresscompressive stress

No-craks and negligible bowing, due to the small and compressive strain.



CONFIDENTIAL

repeat

22

Epitaxy platform(MOCVD deposition sequence)

Si wafer setting GaN deposition

Cleaning

(Out-situ)

Baking

(In-situ)

GaN depo-ed

Carrier ‘ finished’

wafers

repeat +

GaN-on-Si

Sapphire wafer setting GaN deposition

+

GaN depo-ed

Carrier

‘ finished’wafers

GaN-on-Sapphire

vs.

The growth can run consecutively many times without interruption.



CONFIDENTIAL 23

PackagingConventional Power packaging

Total thermal Resistance is so large, even though the chip itself has a small thermal resistance.

The reason is Si-IGBT has the drain in the bottom, therefore a thick insulator has to be sandwiched.

Why?

Direct bonding Cu (DBC substrate)

chipsolderCu

insulator

solder

Base plate

grease

Cu

Heat sink

Heat flow



CONFIDENTIAL

Un-disclosed, todaySorry!

24

packaging Direct attachment onto the printed-circuit board( PCB)

Changes the concept of packaging!

No wire-bonding The bear chip is placed directly to

the PCB board.

So, what is it?



CONFIDENTIAL 25

Heat dissipation technique

Sapphire has lower thermal conductance than Si and SiC .

sapphire Si SiC

38 140 400

Thermal conductance [W/m K]

Then, how do we overcome this dis-advantage in terms of heat flow?

GaN devices are made on sapphire substrate.



CONFIDENTIAL


Solution is “Direct contact between the chip and the heat-sink”

Heat spreader

0.5

Solder 0.05

1.0

0.05

Sapphire 0.12

4 mm4 mm

grease

soldersapphire

velocity 1m/s. 4m/s

4 mm

water

Heat spreader

Heat-sink

sapphire

grease

Device width

solder

Chip insidePCB board



CONFIDENTIAL

Cu-stage(0.5mm)

Sapphire(120um)

Grease(50um)Cu-spreader

(1mm)

Solder(50um)

Water 20

30

40

50

60

70

0 500 1000 1500 2000

40W/chip (4x6 mm2)

Tem

pera

ture

[ o

C ]

Depth from Channel, center [ um ]

water: 1 [m/sec]

water: 4[m/sec]

Temperature profile

Results of 40 [W/chip] input energy

grease

soldersapphire

水流速 1 [m/s]


Temperature contour

Dep

th

65.8 oC

65.8 oC

Max. temperature increase was 45.8 oC (water velocity =1 m/s), 35 oC (water velocity =4 m/s)

Very high efficient heat-transfer

Heat spreader

Heat sink

water temp.



CONFIDENTIAL 28

3

4

5

6

7

8

0 100 200 300 400 500

Time response of currentunder the no-air-blowing condition

Cu

rre

nt

[ A ]

Time [ s ]

Ron : 160 m

GaN PSJ

SiC-MOS ( SCT2160KE )

Heat dissipation techniqueOne more evidence;

Compare with a commercial SiC MOS-FET packaged in standard TO-247.

A

socket

V

• No air-blowing• No heat sink• Vertical standing• Constant voltage

The currentｓ decrease with time due to the temperature increase.

The SiC sample decreases larger than the POWDEC GaN sample, indicating SiC’s larger thermal impedance.

(condition)



CONFIDENTIAL 29

Summary

Today’s main stream GaN power technology,(Field-plate GaN-FET on Si substrate) is being encountered sever challenges in terms of high-voltage and mass-productivity.

GaN PSJ technology platform has a

potential to replace the present Silicon counterparts due not only to the performance but also the production cost.

謝謝


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