Physical & Electronic Properties

Physical & Electronic Properties

The physical and electronic properties of SiC make it the foremost semiconductor material for short wavelength optoelectronic, high temperature, radiation resistant, and high-power/high-frequency electronic devices.
A summary of the most important properties in comparison to Si and GaAs is shown below:

Wide Energy Bandgap (eV)

4H-SiC: 3.26

6H-SiC: 3.03

GaAs: 1.43

Si: 1.12

Electronic devices formed in SiC can operate at extremely high temperatures without suffering from intrinsic conduction effects because of the wide energy bandgap. Also, this property allows SiC to emit and detect short wavelength light which makes the fabrication of blue light emitting diodes and nearly solar blind UV photodetectors possible.

High Breakdown Electric Field [V/cm (for 1000 V operation)]

4H-SiC: 2.2 x 106*

6H-SiC: 2.4 x 106*

GaAs: 3 x 105

Si: 2.5 x 105

SiC can withstand a voltage gradient (or electric field) over eight times greater than than Si or GaAs without undergoing avalanche breakdown. This high breakdown electric field enables the fabrication of very high-voltage, high-power devices such as diodes, power transitors, power thyristors and surge suppressors, as well as high power microwave devices. Additionally, it allows the devices to be placed very close together, providing high device packing density for integrated circuits.

High Thermal Conductivity (W/cm · K @ RT)

4H-SiC: 3.0-3.8

6H-SiC: 3.0-3.8

GaAs: 0.5

Si: 1.5

SiC is an excellent thermal conductor. Heat will flow more readily through SiC than other semiconductor materials. In fact, at room temperature, SiC has a higher thermal conductivity than any metal. This property enables SiC devices to operate at extremely high power levels and still dissipate the large amounts of excess heat generated.

High Saturated Electron Drift Velocity [cm/sec (@ E 2 x 105 V/cm)]

4H-SiC: 2.0 x 107

6H-SiC: 2.0 x 107

GaAs: 1.0 x 107

Si: 1.0 x 107

SiC devices can operate at high frequencies (RF and microwave) because of the high saturated electron drift velocity of SiC.

      Collectively, these properties allow SiC devices to offer tremendous benefits over
      other available semicondutor devices in a large number of industrial and military applications.

     * Measurement parallel to c-axis.

    Applications and Benefits for Devices Fabricated From
   4H-SiC and 6H-SiC Substrates




· Solid state phased array radar systems

· Increase output power of solid state RF devices by factor of 4

· Communication Systems

· Reduce system weight and volume

· Solid state UHF broadcast systems

· Operate in elevated temperature and high radiation environments

· High frequency power supplies

· Reduce device cooling requirements

· Electronic countermeasures- jamming and threat
  warning systems

· Offer power densities that are 4 times higher than Si or GaAs devices



· Power electronics for power generating systems

· Lower voltage drop for unipolar devices

· Surge suppressors

· Up to 100 times the power density of Si devices

· Power conditioning for electric vehicles

· Increased number of power devices per unit area

· Electronic actuators

· Reduced size and weight of cooling systems

· Solid state lamp ballasts

· Excellent transient characteristics including high switching speed and the elimination of large reverse-recovery currents



· Jet engine sensors, actuators and control electronics

· Sensor output signal amplification at high temperatures

· Spacecraft power conditioning electronics and sensors

· Reduce or eliminate need for cooling of engine electronics

· Transmitters for deep well drilling

· Aircraft weight savings - sensor amplification at point of measurement eliminates need for heavy shielding conduit for small signal transmission

· Industrial process measurement and control instrumentation

· Reliable sensing and control in aggressive environments not currently served by solid-state electronics

· Distributorless electronic ignitions

· Reduce size and weight of satellites and space platforms by allowing electronics to operate at higher temperature

· Automotive engine sensors

· Improved device reliability due to long term chemical and thermal stability at elevated temperatures



· Full-color displays

· High reliability

· Full-color photographic slide scanners and film exposure systems

· Blue LEDs used together with red and green LEDs allow the production of solid state light of any color in the visible spectrum

· Indicators for instrumentation and consumer electronics

· Detectors operate at >350ºC while maintaining excellent efficiency

· Blood-oxygen analysis

· Nearly solar blind detection (99% of the response is in the UV range)

· Air quality monitoring equipment

· PN junction leakage currents 104 - 105 times less than Si junctions for sensitivity up to 10,000 times greater than common Si based UV photodetectors

· Solid state flame detectors for combustion control

· Low dark current eliminates need for cryogenic cooling

· UV dosimetry for industrial processes

· UV spectroscopy

· Incoming ballistic missile detection and imagine





· Blue LEDs

· Close match of lattice parameters and coefficient

· Blue laser diodes

· High thermal conductivity substrate offers greater power handling and improved reliability.


· Electrical conductivity allows vertical device structure


· Best technological approach for short wavelength laser diodes, which significantly increase optical storage capacities

· Green LEDs

· Electrical conductivity which ranges from insulating for microwave devices to conducting for LEDs and laser diodes

· UV Emitters

· HBTs