The advantages of Infineon’s CoolSiC™ technology

Silicon Carbide MOSFETs are based on a so-called wide bandgap material, they complement the existing portfolio of IGBTs and MOSFETs and address power ranges of typically more than 1 kilowatt and enable several hundreds of kilohertz switching frequency.

But what is the magic of wide bandgap?
The wider bandgap directly correlates with the breakdown field. A higher breakdown field results in higher voltage operation for a given dimension compared to silicon (thinner active layers), which then results in extended power density and higher-frequency switching. Furthermore, due to outstanding thermal conductivity, improved heat dissipation can be leveraged.

The thinner active layers contain also a higher number of free electrons and consequently a lower sheet resistance RS, giving designers the possibility to use unipolar Silicon Carbide devices for higher blocking voltages, where IGBTs are used typically.

Furthermore, compared to IGBTs, Silicon Carbide offers reduced switching losses, knee voltage-free on-state, and integrated free-wheeling diodes, and therefore a reduced number of components can be realized.

What are the target areas of Silicon Carbide?
While Silicon will stay mainstream technology for the next decade, there are some applications, where it makes sense to assess the cost-performance ratio enabled by SiC already today. Although the cost for Silicon Carbide MOSFETs is higher, the benefit can be achieved on a system level; in that case, we have reached the so-called tipping point.

• 1.  Photovoltaic
  The power density of a solar string inverter can be increased by a factor of 2.5 with CoolSiC™ compared to Si IGBTs. In addition, the number of switches can be reduced – 3-level instead of 5-level solutions, which brings less risk of failures. Finally, the system efficiency is at 99.1% compared to 98.9%.


• 2.  Uninterruptible power supply (UPS)
  Thanks to CoolSiC™ the power losses are reduced by more than 40%. The cost for running a 1 MW UPS system operating at 50% load for 5 years can be reduced by almost 50% when exchanging a Silicon-based 2-level solution with the disruptive SiC 2-level solution.


• 3.  Servo Drives
  Building servo drives with CoolSiC™ MOSFETs results in loss reductions in all operating modes, with up to 80% system loss reduction.
  The heatsink can be up to 60% smaller or even fan-less drives can be realized, which means less maintenance.
  In addition, the cabling can be reduced since compact inverter integration, directly on a motor, becomes possible.

What is so special about Infineon’s SiC technology?
When developing the CoolSiC™ MOSFET, Infineon weighed the following aspects up against each other: reliability, system compatibility, robustness, volume, and manufacturing capability as well as cost position.

It then was concluded to base the Silicon Carbide solution on a trench concept. Compared to the competition’s planar solutions, CoolSiC™ features:

• -  Superior gate oxide reliability
• -  Threshold voltage V_th > 4 V
• -  Short-circuit robustness of 2 µs
• -  IGBT-compatible gate driving +15 (18 V) for turn-on
• -  Suppressed parasitic turn-on
• -  Turn-on at 0 V possible

CoolSiC™ is hence as robust and reliable as Silicon, but at a higher performance level.

What makes Infineon the quality leader?
Since there are material-specific failure modes, Infineon goes beyond the standard qualification process with dedicated tests and extended screening procedures.

For example, in addition to the automotive stress test AEC-Q101 or the industrial JEDEc standard, Infineon monitors:

• -  More temperature cycles
• -  Longer HTRB hours
• -  High voltages, transients, and overshooting
• -  New scenarios for climatic tests and dynamic test patterns

The scope of reliability testing has consequently been extended to reflect the application requirements and field conditions.

Key features

• CoolSiC™ MOSFET vs. competition
• •  Superior gate oxide reliability
• •  Threshold voltage V_th > 4 V
• •  Short-circuit robustness, 2 µs
• •  IGBT-compatible gate driving, +15 (18 V) for turn-on
• •  Suppressed parasitic turn-on
• •  Turn-on at 0 V possible

General applications

• •  Photovoltaic
• •  UPS
• •  Servo Drives
• •  EV Charging
• •  Energy Storage Systems
• •  Server and Telecom
• •  e-Mobility main inverter
• •  e-Mobility On-board-charger

Related articles

Webinar: An Introduction to Infineon’s CoolSiC™
Whitepaper: How Infineon controls and assures the reliability of SiC based power semiconductors
Become an expert in Silicon Carbide technology with Infineon
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