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Silicon Carbide

A wide-bandgap technology used for FETs and MOSFETs for power transistors.


Based on silicon and carbon, SiC is used in LEDs and power electronics. SiC has a bandgap of 3.3 eV. Silicon has a bandgap of 1.1 eV. Wide bandgap refers to higher voltage electronic band gaps in devices, which are larger than 1 electronvolt (eV).
Today, SiC diodes are used in high-end power supplies for servers and telecom systems, but SiC MOSFETs are still in the early stages of market penetration. Compared to power MOSFETs, SiC has 10 times the breakdown field and three times the thermal conductivity.

SiC FETs are targeted for 600-volt to 10-kilovolt applications.

But SiC also suffers from high wafer costs and low effective channel mobility. In a move to address some of the issues, suppliers hope to reduce the costs by moving to larger wafers. Today, SiC-based LEDs are made on 150mm wafers. SiC-based FETs are using 100mm substrates.

SiC MOSFETs are vertical devices. The channel structures also come in various configurations, including trench and planar. Planar tends to be simpler. Trench-based SiC MOSFETs have lower conductivity loses than planar. But trench tends to suffer from gate-oxide breakdowns, prompting some to devise double-trench SiC MOSFETs.