REFLECTOR LAYERS - DBRs & HYBRIDSReflector layers that shine out in LED production

• Sputter processes for sensitive substrates and sub layers

• Reflectivities close to 100%

Relative to the metallic reflectors, so-called hybrids (metal/

dielectric combinations) and Distributed Bragg Relectors

“DBRs” (full dielectric stacks) offer near 100% reflectivity,

improving device extraction efficiency and light output

according to type of LED design.

Evatec’s cathode technology on the Radiance platform

allow dielectric stacks with the widest reflection band to

be deposited accurately and repeatibly. Plasma Emission

Monitoring for enhanced layer stoichiometry control and

in situ broadband monitoring for precise layer end point

termination enable tight process control for film designs with

large numbers of layers requiring the greatest accuracy.

The Radiance system and process geometry also protects

damage and temperature sensitive substrate materials and

helps thin film engineers to develop new device designs and

materials for the next generation LEDs.

Evatec’s hybrid and DBR stack solutions are tailored in

cooperation with customers according to:

- Substrate material

- Wavelength range

- Device geometry, angular range

- Device packaging

Photo courtesy of OSRAM

Product descriptions, photos and data are supplied within the brochure for general information only and may be superseded by any data contained within Evatec quotations, manuals or specifications.

Evatec Ltd.Lochrietstrasse 14CH-8890 FlumsSwitzerlandTel: + 41 81 720 1080Fax: + 41 81 720 1081info@evatecnet.comwww.evatecnet.com

REFLECTOR LAYERS - DBRs & HYBRIDS

Typical Dielectric Stack Materials

Material Refractive Index @500 nm

Transmission range [nm]

TiO2 2.40 400 - 12000

Nb2O5 2.35 380 - 7000

Ta2O5 2.1 350 - 7000

HfO2 1.90 230 - 7000

Al2O3 1.63 200 - 5000

SiO2 1.46 200 - 2000

MgF2 1.38 150 - 7000

Optical performance for typical DBR Mirror

Stack design 25 layers SiO2 / Nb2O5 on Sapphire substrate

Optical performance for typical Hybrid Mirror

Stack design 13 layers Al / Nb2O5 / SiO2