Evatec LAYERS 4 2018-19 - Optoelectronics

EDITION 4

OPTOELECTRONICS Helping customers take advantage of new opportunities in LED & VCSEL EXTRACTS FROM LAYERS 4

CHAPTER

OPTOELECTRONICS Optoelectronics – Meet the Team Industry trends by Yole Développement LED or LASER – Evatec has the solution!

Hot sputtered ITO – A new opportunity

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LAYERS 4 | OPTOELECTRONICS | MEET THE TEAM

OPTOELECTRONICS TAKING ADVANTAGE OF NEW MARKET OPPORTUNITIES OPTOELECTRONICS LED LASER/VCSEL Micro Display

Whether its in LED, VCSEL or Micro Display, Evatec’s thin film platforms and process know-how can help manufacturers secure exciting new opportunities over the coming years. Franz Xaver and I look forward to delivering tailored production solutions that maximise your profitability.

Dr. Stefan Seifried Head of BU Optoelectronics Stefan is a chemist and materials scientist gaining his PhD in coating technology in Germany in 2002. He has 15 years experience of technical, business and company leadership in the engineering, vacuum and semiconductor industries including capital equipment for thin film processes in hard disk manufacturing.

Stefan

Optoelectronics

Franz Xaver Lenherr Product Marketing Manager Franz Xaver joined Evatec in 2018.

He has 20 years experience in engineering, project and business management within vacuum processing and semiconductor fields and knowhow in a wide range of coating applications including optical disk. In 2017 he completed an executive MBA in Switzerland to complement his earlier training in electrical and mechanical engineering.

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LAYERS 4 | OPTOELECTRONICS | INDUSTRY TRENDS

INDUSTRY TRENDS: OPTOELECTRONICS We are only scratching the surface of potential of optoelectronics Over the past 20 years, the strong growth in optoelectronics has been fueled by different technologies at different times. Laser diodes for highspeed optical networks were a major growth driver before the “dot.com” implosion in 2001. PV1, image sensors and LED2 devices then became star performers through the 2000s, followed by OLED3 and Quantum Dots in the 2010s.

More recently, there has been a lot of hype on Micro LED, VCSEL4 or 3D sensing / imaging technologies, and silicon photonics remains a good example of a booming trend in this domain.

Optoelectronic technologies are mostly driven by integration into industrial, automotive and consumer

products (e.g.: smartphones, VR/AR5 headsets…) as enabling intelligent next-generation systems. Typical examples include VCSEL technology at the heart of Apple’s iPhone X FaceID function, matrix LED systems enabling intelligent glare-free lighting functions in recent car models, EELs6 representing key enabling technologies for LiDAR and so to autonomous driving while OLEDs7 and QDs8 are now at the heart of the display industry.

We are, therefore, only scratching the potential of optoelectronic technologies and related market opportunities. Already a multi-billiondollar industry at the component level, the optoelectronic business will continue to grow strongly in the next decade as long as already established

VCSEL market forecast by segment Source: VCSELs – Technology, industry and market trends report, Yole Développement, 2018

2023 US$ 3,500M

2017 US$ 330M

US$ 165 M

CAGR: +48%

US$ 105 M

US$ 3,100 M

US$ 80 M

US$ 46 M US$ 205 M

US$ 86 M

Consumer

Datacom

Industry

Automotive

technologies (e.g. LED, PV) continue to increase their penetration rate, and disruptive technologies / systems (e.g.: 3D sensors / imagers) are developed.

Although VCSELs have existed for 20+ years, mainly for short-distance data communications (e.g. datacenters), they were relatively unknown until Apple used three of them in the iPhone X to enable its 3D sensing and facial recognition functions.

This move from the smartphone giant subsequently generated huge interest in the technology from other smartphone manufacturers as well as all other players across the supply chain. Less than one year after the release of Apple’s flagship, its competitors are following the trend and starting to integrate 3D sensing technologies. Xiaomi and Oppo were the quickest on the draw but other leading players like Huawei, Vivo and Samsung are also expected to integrate VCSELs into their next flagship models. For this reason, the explosive increase in demand for VCSELs, which started in 2017, will persist for the next five years, potentially multiplying the business opportunity more than tenfold: from US$330 million in 2017 to nearly US$3,500 million in 20239.

At the industry supply level, VCSEL integration into smartphones increased tension throughout the supply chain - partly because Apple’s iPhone used a large portion of its suppliers’ existing capacity, and also because new business opportunities were emerging practically overnight for players at all points of the supply chain. As a result, leading VCSEL

Optoelectronics

MicroLED are Small!

Source: SID 2018 Symposium Speaker: Eric Virey from Yole Développement 0.001

0.01

0.1

1

10

100

1000

Pollen

Biological Contaminants

0.0001

25 million microLED chips, each the size of a bacterium, with a placement accuracy of 1 µm or less.

Mold Spores House Dust Allergenes Bacteria Cat Allergenes Viruses

Types of Dust

Heavy Dust Settled Dust Suspended Atmospheric Dust

Gas Molecules

Particulate Contaminants

Cement Dust

0.0001

Fly Ash Oil Smoke Smog Tobacco Smoke Soot Gaseous Contaminants

0.001

Micro Leds 0.01

0.1

1

10

100

1000

This technology is nevertheless progressing on all fronts and the emergence of microLED consumer displays appears increasingly realistic. There are challenging but credible cost-reduction paths for both TVs and smartphones toward levels compatible with penetration in high-end market segments, in competition with OLED. Small panels for smartwatches and microdisplays for Augmented Reality and Head Up Displays could be the first commercial applications, with smartphones and TVs to follow.

Comparison of µLED dimensions vs. atmospheric particles Background graph: Wikipedia, concept courtesy of Allos Semiconductor

manufacturers are moving from datacoms to the consumer market, and several new entrants are trying to get their piece of the cake. But VCSEL manufacturing for consumer applications is complex and there is a lengthy period of process optimisation between R&D and production.

Recently, there were several M&As in this field (e.g. II-VI, ams, Osram) and Yole Développement anticipates more in the coming years as it seems to be only the beginning of the success story for the technology.

In a parallel development, micro LEDs for display applications also play a significant role in the optoelectronic industry today. MicroLED displays could potentially match or even exceed OLED performance in all critical attributes such as brightness, contrast, color gamut, refresh rate, viewing angle, ruggedness and durability, lifetime, efficiency etc.

Excitement about this technology grew in 2014 after Apple acquired Luxvue, the microLED display startup.

Since then, many large consumer electronics and semiconductor companies such as Facebook-Oculus,

Google, Sharp-Foxconn, Samsung, LG, Intel, etc., have entered the field.

More than 120 companies or research organizations have already filed about 1500 patents in more than 500 patent families.

The technology is inherently complex.

Just like OLED, micro LED is a selfemissive display: each subpixel is an independently controllable light source. However, unlike OLED, there are no technologies allowing the deposition of blanket LED layers over large area substrates (up to 5.5 m2 in the case of OLED Generation 8.5 fab, and soon 9.9 m2 on upcoming Generation 10.5!).

LED emitters are grown by traditional semiconductor technologies on 4 to 8” wafers and the art of making a micro LED display consists of patterning and singulating tiny LED emitters (less than 10 or even 5 µm for most consumer applications) and assembling them on a backplane which incorporates the circuitry to drive individual subpixels.

To put this in perspective, for a 4K display (3,840 x 2,160 resolution), this implies assembling and connecting

1. PV : Photovoltaic 2. LED : Light Emitting Diode 3. OLED: Organic LED 4. VCSEL: Vertical Cavity Surface Emitting Laser 5. AR/VR : Augmented Reality/Virtual Reality 6. EEL : Edge Emitting Lasers 7. OLED : Organic LED 8. QD : Quantum Dot 9. Source : VCSELs - Technology, Industry and Market Trends report, Yole Développement, 2018

Since 2015, Pars Mukish has taken on responsibility for developing SSL and display activities as Business Unit Manager at Yole Développement where he is a member of the Photonics, Sensing & Display division. Previously, Pars worked for several years as Marketing Analyst and Techno-Economic Analyst at the CEA (French Research Center).

Dr. Eric Virey is a Senior Market and Technology Analyst at Yole Développement, within the Photonic & Sensing & Display division. Eric contributes to the development of LED, OLED, and display activities, including a large number of market and technology reports as well as custom consulting projects.

Previously Eric has held various R&D, engineering, manufacturing and business development positions with Fortune 500 Company Saint Gobain.

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LAYERS 4 | OPTOELECTRONICS | LED OR LASER

LED OR LASER – EVATEC HAS THE SOLUTION!

Optoelectronics

As the VCSEL (Vertical Cavity Self Emitting Laser) market booms due to their emerging use in 3D sensing applications for mobile phones, Evatec’s Head of BU Optoelectronics Dr. Stefan Seifried explains how Evatec can help VCSEL manufacturers ramp up production leveraging its know how from LED.

The VCSEL market will explode VCSEL technology may not be new, the first components were commercialised by Honeywell over 20 years ago in 1996, but the introduction of VCSEL technology in mobile applications in 2017 looks set to drive a 10 fold increase in demand over the next 5 or 6 years.

Relative to technologies like LED, VCSEL offers coherent, symmetrical, low divergence optical beam technology (typically 15 degrees) giving it a high degree of usable optical emission as a semiconductor optical source. Just

Attribute

like LEDs however It offers a high efficiency around 20% but its planar structure with vertical emission means it can be tested during wafer processing before sawing and building higher level assemblies. (see table 1 & 2) Some analysts such as Yole expect that the upcoming demand for consumer devices including front side for face recognition and rear side for 3D simulation applications for clothing / furniture plus applications like LiDAR could lead to growth of market volumes to US$ 3500 Million by 2023.

Symbol

Units

EE Laser

LED

Electrical power

Pelec

mW

5

20

60

60

Optical power

Popt

mW

1

5

10

1

Efficiency at Popt=1mW

h

%

20

10

10

2*

Wavelength

I

nm

760 - 860

670 - 870

630 - 1300

400 - 1300

∆λ

nm

0.01

0.5

2

50

Spectral tuning (Temperature)

∆λ / ∆T

nm/ºC

0.06

0.06

0.3

0.3

Spectral tuning (Current)

∆λ / ∆I

mm/mA

0.25

0.09

º

<15

~ 15

15 par.

35 prpe

120

Spectral width

Beam angle (full width at half of maximum value)

SM VCSEL MM VCSEL

Table 1: Comparison of performance (Courtesy of Finisar)

The “ilities” of VCSEL Manufacturability Integrability

Reliability

Testability

Arrayability

Packageability

All-vertical construction enables the use of traditional semiconductor manufacturing equipment

Without the failure modes of traditional laser structures such as dark line defects and catastrophic optical damage; very long wearout life

Complete testing and burn-in in wafer form

VCSELs can be easily fabricated into one or two dimensional arrays

VCSELs allow use of traditional low cost LED packaging; chip on board technology for VCSEL-based sensors

Compatible with semiconductor manufacturing and wafer integration of the emitters with detectors and circuitry

Table 2: (Courtesy of Finisar)

Low power consumption Not strictly an “ilitiy” – extends battery life and reduces thermal design constraints in larger equipment systems

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LAYERS 4 | OPTOELECTRONICS | LED OR LASER

Using the experience from LED Evatec has over 10 years experience in supporting the worlds leading LED manufacturers with sputter and evaporation processes. On one hand we could help them increase device performance by improving light output and other LED device properties, but on the other hand we also helped them implement processes driving down costs. ITO production on our CLUSTERLINE® RAD (CLN RAD) as well as “lift off” processes on BAK evaporator family are now LED industry standard. Sharing their device requirements, the real device performance data achieved and their new ideas, they worked together with Evatec optimizing processes to create a successful LED business, irrespective if it was a more cost-driven LED commodity-product for the lighting industry or a high power LED device for an automotive application.

Just like in LED, the explosion in demand for VCSEL will now set manufacturers the same challenges in driving up device performance, improving manufacturing yields, and lowering production costs.

Applying VCSEL to 3D sensing applications A time of flight (TOF) sensor in a typical mobile phone first illuminates an object in front of the phone repeatedly at a very high rate, measuring the time taken for light to reflect or scatter back to a detector. If the TOF sensor detects an object, it triggers a True Depth camera to take a picture. If that reveals a face, the phone activates its dot projector, shining a single infrared VCSEL through an optical system to create 30,000 spots while its infrared camera captures an image. It sends both regular and spottily illuminated IR face images to an application-processing unit (APU) that can recognise the owner and therefore unlock the phone.* Just like in LED technology, the VCSELs for NIR laser diodes used for mass production of 3D sensing and other applications use cost-optimised device designs. There are a wide range of VCSEL applications and designs on different substrate materials including silicon, aluminum oxide or GaN with specific power levels and ranges of wavelengths as shown below.

Typical VCSEL designs and operating wavelengths

“The VCSEL market growing by a factor 10 over the next 6 years”

AlGalnP/AlGaAs for Red wavelength (650-680nm) VCSELs GalnAsP/AlGaAs for Near-IR wavelength (780-850nm) VCSELs AlGalnAs for wavelength 850nm VCSELs GalnAs for Long-wavelength ( l .3-l.55µm) VCSELs Sb for Long-wavelength ( l.3- l.55µm) VCSELs lll-V Nitride for Visible wavelength VCSELs

Typical VCSEL structure RIE p-GaN

TiO2/SiO2 p-AlGaN

p-electrode

ITO InGaN/GaN n-electrode

p-GaN n-GaN

AlInN/GaN

GaN

* Source: SPIE Newsroom, April 2018

Optoelectronics

Evatec production solutions are ready Evatec’s equipment and process portfolio Whatever the VCSEL design, many of the thin film layers required are similar to those required for LED, and Evatec’s equipment and process portfolio for VCSEL manufacturing covers all material types dependent on the device structure.

For metals

n/p contact electrodes with BAK lift-off evaporators.

For surface metals

e.g. TIW – Au sputtering in our dynamic CLUSTERLINE® RAD or static in our Semiconductor production proven CLUSTERLINE® 200 (CLN 200) depending on maximum temperature and step coverage requirements.

For TCOs

Typically ITO we can use either the damage-free ITO process on our CLUSTERLINE® RAD or the widely proven ITO process of our high-speed SOLARIS® system. For future high throughput / low damage requirements a combination of Facing Target Cathode (FTC) process for contact and fast sputter process for bulk layer is ready.

For the optical mirror layer stacks

We can deliver different options depending on the number of pairs forming the DBR stack. Above 20 pairs (e.g. NbO2 / SiO2 ) the CLUSTERLINE® RAD with high uniformity deposition of typically < 0.25% and in-situ process control features for optical thickness (GSM) and the plasma emission monitoring to control deposition rate and film stoichiometry would be beneficial, while for less complex optical interference coatings (OIC) our SOLARIS® would provide significant cost of ownership advantages thanks to higher throughput.

Other custom layers

The portfolio can be concluded with additional applications for anti-reflective and/or passivation layers using sputtering or PECVD or additional metals e.g. heat sinks.

Application

PVD Equipment

Process

Contact Metals Lift-off: n/p-contact Surface Metal TiW-Au sputter

BAK

CLUSTERLINE® RAD

CLUSTERLINE® 200

Dielectric DBR Top - DBR

CLUSTERLINE® RAD

MSP

ITO damage-free ITO ITO

CLN RAD, MSP, SOLARIS®, Top DBR TiO2 / SiO2 Ta2O5 / SiO2 NbO2 / SiO2 a-Si / SiO2 CLN RAD / SOLARIS® ITO, damage-free ITO

CLUSTERLINE® RAD

Dieletrics SiN PECVD pass SiO2 PECVD/PVD Diamond, heat sink SiN AR

SOLARIS®

BAK: Evap lift-off n-contact: Ti-Pd-Au-Ge P-contact: Ti-Pd-Ti-Au-Sn CLN 200 / CLN RAD Etch - TiW - Au seed

SOLARIS®

CLN 200 / SOLARIS® SiO2 PECVD SiN AR, Diamond CLUSTERLINE® 200

SOLARIS®

Get off to a quick start Our applications team is ready to help you with a production solution that’s tailor made for you according to substrate size, process and throughput. Our processes are available for fully automated cassette-to-cassette operation and with proven particle performance. Minimizing human interactions enables high-yield mass production of either discrete VCSELs or as part of more highly integrated devices.

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LAYERS 4 | OPTOELECTRONICS | HOT SPUTTERED ITO – A NEW OPPORTUNITY

HOT SPUTTERED ITO – A NEW PROCESS IN THE LED PORTFOLIO Evatec Product Marketing Manager Franz Xaver Lenherr introduces the new “hot turn table” available on CLUSTERLINE® RAD and the new possibilities it offers to LED manufacturers for ITO deposition.

New opportunities

Take a look at the results

Although cold ITO deposition processes may be well established, there are always new applications and products in development requiring different material properties.

Figure 1 shows a range of typical hot sputtered films all deposited at the same temperature. Just like for cold processes varying other process conditions allows effective control of grain size.

Changing sputter deposition conditions for materials like ITO could bring other opportunities. Deposition temperature affects the grain shape and the combination of a temperature controlled hot ITO sputter process followed by an annealing process could enable new layer characteristics to be achieved including lower sheet resistance and higher transmission. Heating using traditional front side heating systems extends process times and reduces throughput which is problematic, but that issue can now be avoided with the new “hot turn table” available on CLUSTERLINE® RAD.

Figure 2 compares the structures achieved for a cold process with anneal and a hot process without any subsequent anneal. Like always, layer deposition conditions and properties need to be optimised for each manufacturer and device structure and considered in relation to other downstream processes required, but in some cases running a hot process could eliminate the need for a subsequent post deposition anneal.

Optoelectronics

RESULTS Grainsize variations for “HOT” sputtered films Fig. 1

After anneal: Cold sputtered

As deposited: Hot sputtered

Fig. 2

Same process conditions These pictures are the same size The red square = picture size 1µm x 1µm

5 x 5 µm

Developing a practical heating solution The new “hot turn table” available on CLUSTERLINE® RAD is designed to facilitate such processes in mass production . An individual backside heater for every chuck ensures precise, repeatable surface temperature for each single substrate for tailoring of optimised layer structure.

Each unit consist of three individual heating elements, resulting in best heating uniformity over the chuck diameter of 150 mm with variation of less than 3% at a temperature of 325°C over the total surface diameter.

Temperature uniformity of individual chuck at 280°C

The temperature itself can be adjusted between 100°C and 350°C max with a variation of maximum 5% over the full temperature range. Pyrometers in closed loop control measure, and adjust each individual chuck position around the turntable. Heating is confined to exactly where its needed and each chuck body also comes with integrated cooling

Concept of the hot ITO turntable with individual chuck segments and its cooling supply.

All CLUSTERLINE® RAD customers can benefit This new turn table feature is configurable for any new CLUSTERLINE® RAD order. However we can also retrofit existing systems to the same configuration.

To find out more simply contact your local Evatec Sales and Service Organisation.

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