F R A U N H O F E R U S A C E N T E R F O R C O AT I N G S A N D D I A M O N D T E C H N O L O G I E S

SINGLE CRYSTAL DIAMOND

IN COOPERATION WITH

Overview

Our Offer

Fraunhofer USA

1449 Engineering Research Ct.

East Lansing, MI 48824, USA

Contact

Thomas Schuelke, Director

Phone: +1 517 4328709

ccd-info@fraunhofer.org

ccd.fraunhofer.org

Center for Coatings and

Diamond Technologies (CCD)Single crystalline diamonds (SCD) haveextraordinary physical properties, makingdiamond the material of choice for manychallenging applications. Diamond is notonly the hardest material, it also offers aunique combination of properties relevantto high power and high frequency electronicapplications:

Diamond electronics can operate about 10times more efficiently than SiC. This allowsfor a reduction in device cooling and increasedsafety. Diamond can be doped using boron

(p-type) and phosphorus (n-type) during growth.

Single crystalline diamond and its dopedvariations can be produced using chemicalvapor deposition technology. Similar to thedevelopment of silicon carbide and galliumnitride wafers it is expected that ever largerdiamond plates will become available andthus further reduce the costs of the materialfor electronic devices and other applicationdevelopment.

1. SCD deposition on 70 samples simultaneously

2. Rounded ATR diamond

3. SCD plates

1 2 3

Highest thermal conductivity of2200 W/m·K

Widest band gap of 5.45eV

Largest electric breakdown field of10 V/cm

Highest saturation electron driftvelocity of 2.7·10 cm/s

6

7

CCD offers the development of single cryst-alline diamond material tailored to customerspecifications. Products are freestandingSCD plates of up to 8×8 mm in size andcrystals shaped for specific applications. Ourin-house fabrication capabilities enable mat-erial development and prototype productionof complex SCD products.

2

SCD Growth

2018

SCD Products

Optical grade intrinsic SCD diamond can beused for:

Electronic grade intrinsic and doped singlecrystalline diamond can be used for:

Attenuated Total Reflection(ATR) crystals

Raman laser crystals

Raman probes

Heat spreaders

X-ray optical components

Freestanding SCD plates(diamond wafers)

Gemstones

Optical Windows

Radiation detectors

Spin electronic devices

High power high frequencyelectronic devices

Single crystal diamond is grown by in-housedeveloped state-of-the-art microwave plasmaassisted chemical vapor deposition technology.High process pressure synthesis at 380 Torr(0.5 atm) achieves more than 1 mm of homo-epitaxial diamond growth per day. Whenusing 8×8 mm seed crystals this rateproduces more than 1 carat of diamond perday per seed. Post-processing includes lasercutting and mechanical polishing to obtainfreestanding plates and shaped crystals.

A diamond synthesis process was developedto produce optical grade type IIa SCD mate-rial. The nitrogen content in the fabricatedcrystals are less than 100 ppb and there islittle optical absorption for photon energiesbelow the bandgap (wavelengths greaterthan 225 nm).

In-house post diamond growth fabricationcapabilities include wet chemical etching,plasma dry etching, mechanical polishingand laser cutting.

Grown SCD material is sliced off its seedcrystal via laser cutting. After mechanicalpolishing, freestanding high quality crystalsare obtained as a semi - finished product.These crystals can then be formed into dia-mond plates for wafer based applications orthey can be shaped into specific geometriesas requested by the customer (for examplethe attenuated total reflection spectroscopycrystals).

SCD Processing

SCD Devices

CCD has capabilities of manufacturingelectronic SCD devices such as pn - andSchottky - barrier diodes. Device fabricationand characterization is carried out in ourcleanroom facility.

Comparison of Intrinsic Material ThicknessNeeded to Hold-Off 10,000V

1000µm

800µm

100µm 80µm20µm

Silicon GalliumArsenide

GalliumNitride

SiliconCarbide

Diamond

Property (relative to sillicon)

Thermal Conductivity

Thermal Expansion Coefficient

Dielectric Constant

Electron Mobility

Hole Mobility

Saturated Carrier Velocity

Si GaAs GaN

1 1.6 2.2 1.6

1 1.06 0.9 0.9

1 5.67 0.83 0.67

1 0.67 0.42 0.08

1 1 2.2 2

1 0.3 0.9 3.1

SiC

0.03

0.5

3.0

6.3

>2.5

13.5

Diamond

Property (relative to sillicon)

Johnson Figure of Merit

Keyes Figure of Merit

Baliga Figure of Merit

Baliga High FrequencyFigure of Merit

GaAs

11

0.45

28

16

GaN

790

1.6

400

44

SiC

410

5.1

290

34

Diamond

5,800

31

12,500

1,100

Si

1

1

1

1

1. ATR crystal diamonds

1

2