Recent progress in MOCVD Technology for Electronic and Optoelectronic Devices

Prof Dr.-Ing. Michael Heuken1,2

Vice President Corporate Research&Development

1) AIXTRON SE, Dornkaulstr. 2, 52134 Herzogenrath, Germany2) RWTH-Aachen University, Templergraben 55, 52074 Aachen,

Germany

AIXTRON SE

Contents

Introduction

State of the art MOCVD

Micro LED for Displays

Conclusion and Takeaway

Energy saving by using GaN/AlGaN HEMT

The revolution in mobile telephony

3

Compound semiconductor for power control

4

Market opportunities for compound semiconductor

5

Principle of MOVPE

Ga(CH3)3 + AsH3 → GaAs +3CH4

carrier + group III elements+ dopants

carrier + group V elements

wafer

injector

quartz glass ceiling

rotating infrared/inductive heated wafer carrier

Basic understanding of the Planetary Reactor®

radial and horizontal flow of gases above rotating substrates

Gas transport mechanisms in the Planetary Reactor

• Depletion of group-III species results in flat growth rate profile by disc rotation

• Uniformity controlled by balance of convective and diffusive fluxes M.Heuken et al. JCG 303 (2007) 318

8

Resulting growth profile

Distance from center

on rotated waferMOYDJ diff

MOYUJ convect

J = MO species mass flux

= gas density

U = local flow velocity

YMO = mass fraction of MO

D = diffusion coefficient

Dominant species fluxes:

diffusion flux

forced convection flux (by main flow)

Group III

Group V

Group V

Triple injector

NO COMPROMISE IN TUNING:

•Individual wafer rotation and GFR flow control = good on-wafer uniformity by design

•Injector enabling full tuning flexibility

ADVANCED YIELD MANAGEMENT:

•Reset of reactor each run with Cl2 in-situ cleaning No Part Exchange

Excellent Run-to-Run Stability

•Temperature matching between each individual wafers, within a run and run to run

G5+: “Single Wafer performance w Batch reactor cost benefits”

9

Single wafer rotation, combined with radial horizontal gas flow

G5+ 5x200 mm

10

Requirements for MOCVD in HVM:

Cassette-to-Cassette 150/200 mm Si wafer automation for fab integrationand throughput

In-situ Reactor Cleaning for process robustness and yield

On-wafer temperature process control for highest reproducibility and yield

High throughput for lowest Cost-of-ownership (COO)

Qualified device level layer processesfor fast time to market

Cassette-to-Cassette Module

G5+ C Cassette-to-Cassettedual module cluster

Vacuum Robot

AIX G5+ C: CS High-Volume Manufacturing Award 2016

Power Transistor: 100x SL + Active Layers

AIXTRON G5+ C PLANETARY REACTOR® 11

• 100x SL buffer to target 650 V

• Increased carbon level in SL by means of autodoping

• Reference D-Mode device stack with active layers

Bow X (µm) Bow Y (µm)

Sample C 64 44

No strain relaxation even with 100x SL

RT bow comparable to 50x SL

Total thickness: ~5.0 µm

Reflectivity

Curvature

Thickness and AlGaN Barrier Al Composition Mapping

AIXTRON G5+ C PLANETARY REACTOR® 12

• Mean thickness: 4.5 µm*

• STD: 0.4% (3mm EE)

• Mean Al concentration: 27.4%

• STD: 0.50% abs. (3mm EE)

G5+ C features excellent uniformities for both thickness and AlGaN barrier Al composition

*Note: WLI underestimates actual thickness by ~10% due to refractive index averaging

Rsheet

(W/sq)

Carrier density

(1012 cm-2)

Carrier mobility(cm2/Vs)

308 10.2 1998

Hall data:

White Light Interference: Photoluminescence:

I-V Breakdown Characteristics

AIXTRON G5+ C PLANETARY REACTOR® 13

0 250 500 750 1000 1250 150010

-12

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

Forward

Reverse

Cu

rre

nt

(A/m

m2)

Voltage (V)

T = 25 °C

0 250 500 750 1000 1250 150010

-12

10-11

10-10

10-9

10-8

10-7

10-6

10-5

10-4

10-3

10-2

10-1

100

Forward

Reverse

Cu

rre

nt

(A/m

m2)

Voltage (V)

T = 150 °C

800 V / 900 V 600 V / 770 V

650 V specification met at room temperature / very close at 150 °C

1 µA/mm2

0 2 4 6 8 10 120

100

200

300

400

I d (

mA

/mm

)

Vds (V)

E-Mode HEMT: Output Characteristics and Ron Mapping

AIXTRON G5+ C PLANETARY REACTOR® 14

• Power transistor (Wg = 36 mm):

Max current of 13 A in the device

Uniform on-resistance across entire wafer diameter

• On-resistance (Ron) mapping (Wmm):

Vgs =

Intra & Inter wafer layer thickness uniformity & reproducibility

15

Intra-wafer uniformity: σ/mean=0.44%

Inter-run uniformity: σ/mean=0.24%

Inherent process reproducibility delivers highest on-wafer performance at high throughput!

Mean Thicknessin µm

Inter-Run Intra & Inter-Wafer

16

Sources: Texas Instruments, Electronic Products

Selected products – market penetration

Micro LED and it’s potential as emerging display technologyMicro LED opens a new field of opportunities

Large Size Displays

Smart Watches Augmented Reality

TV Display

Smartphone time

Brightness-> Small pixels-> High contrast ratio

Brightness Efficiency-> battery lifetime

Brightness-> compete with ambient light

-> Color Gamut-> Interactive

Brightness-> battery lifetime-> pixels much smaller than pitch allow integration of sensor matrix

Head Up Display-> High Dynamic Range-> High Definition

Larger Wafer Sizes Required for Micro LED Processing

4“ wafer

52 stamps 10mm x 10mm

3mm E.E.

Fill Factor = 75%

6“ wafer

137 stamps 10mm x 10mm

3mm E.E.

Fill Factor = 84%

Assume: 10mm x 10mm Stamps with Pixels for Transfer

• Larger wafer sizes improve wafer utilization• 6” or 8” Requirement driven by Back End Technology Shift

Courtesy: CALY Technologies

Individual Wafer Temperature Control

• Satelite Wafer Temperature measured by a UV Pyrometer

• Gas foil rotation is individually controlled for each satellite (wafer).

• Flying height of satellite over the main disc determines the temperature adjusted by individual flow rate.

Flying Height Temperature

Topside

Temperature

Measurement

Individual

Flow for each

Satellite (Wafer)

Pyro

MFC MFC

MFC M

FC

MFC

PL Wavelength Uniformity Results for Blue LED

2nm

W/W ~ 0.40nmR/R ~ 0.30nm

on-W

0.55nm

DOM = 450.9nm = 0.50nm(3mm e.e.)

BLUEmLED

InGaN /GaN MQW on sapphire in 8x6“ configuration

PL Wavelength Uniformity Results for Green LED

1.7nm

W/W ~ 0.30nmR/R ~ 0.20nm

on-W ~ 0.75nm

InGaN /GaN MQW on sapphire in 8x6“ configuration

GREENmLED

DOM = 525.9nm = 0.60nm(3mm e.e.)

DOM = 627.0nm

= 0.32nm (3mm e.e.)

1.5nm

W/W ~ 0.30nmR/R ~ 0.25nm

on-W

0.40nm

GaInP /AlGaInP MQW on GaAs in 8x6“ configuration

PL Wavelength Uniformity Results for Red LED

REDmLED

Summary & Key Take Aways

23

AIXTRON is developing a complete CVD manufacturing solution forcompound semiconductor based on existing production technology

GaN based Transistors for Power and Microwave Applications

R/G/B Micro LED production technology for future Displays

Business target: Next Generation MOCVD for HVM

If you have any further questions or require more information, please contact us at: Professor Dr. M. HeukenAIXTRON SEDornkaulstr. 252134 HerzogenrathGermanyPhone +49 (2407) 9030-0Fax +49 (2407) 9030-40E-Mai info@aixtron.com

Thank you very much for your attention.