Introduction to Silicon Carbide : Silicon carbide (SiC) is a semiconductor compound composed of silicon (Si) and carbon (C) and belongs to the wide bandgap (WBG) material family. Because of its very strong physical bonding force, the semiconductor has high mechanical, chemical and thermal stability. The wide bandgap and high thermal stability allow SiC devices to be used at junction temperatures higher than silicon, even exceeding 200°C. The main advantage of silicon carbide in power applications is its low drift region resistance, which is a key factor for high-voltage power devices.
The combination of silicon and carbon gives this material outstanding mechanical, chemical and thermal properties, including:
High thermal conductivity
Low coefficient of thermal expansion and excellent thermal shock resistance
Low power and switching losses
High energy efficiency
High operating frequency and temperature (operating up to 200°C junction)
Small chip size (with same breakdown voltage)
Intrinsic body diode (MOSFET devices)
Excellent thermal management to reduce cooling requirements
long life
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What are the applications of silicon carbide in the electronics field?
Silicon carbide is a semiconductor that is well suited for power applications, primarily due to its higher thermal conductivity, higher electron mobility, and lower power losses. Silicon carbide diodes and transistors can also operate at higher frequencies and temperatures without compromising reliability. The main applications for SiC devices, such as Schottky diodes and FET/MOSFET transistors, include converters, inverters, power supplies, battery chargers, and motor control systems.
Why can silicon carbide withstand such high voltage?
Power devices, especially MOSFETs, must be able to handle extremely high voltages. Since the dielectric breakdown strength of the electric field is about ten times higher than that of silicon, SiC can withstand higher voltages, from 600V to several kilovolts. SiC can use higher doping concentrations than silicon, and the drift layer can be made very thin. The thinner the drift layer, the lower its resistance. In theory, given a high voltage, the resistance per unit area of the drift layer can be reduced to 1/300 of that of silicon.
How does silicon carbide achieve better thermal management than silicon?
An important parameter is thermal conductivity, which is a measure of how well a semiconductor dissipates the heat it generates. If the semiconductor cannot dissipate heat effectively, the maximum operating voltage and temperature that the device can withstand are limited. This is another area where silicon carbide outperforms silicon: silicon carbide has a thermal conductivity of 1490 W/mK, while silicon has a thermal conductivity of 150 W/mK.
Although silicon is the most widely used semiconductor in electronics, it is starting to show some limitations, especially in high-power applications. A relevant factor in these applications is the bandgap, or energy gap, that a semiconductor offers. Silicon has a bandgap of about 1.12eV, while silicon carbide has a bandgap value nearly three times greater at about 3.26eV. When the bandgap is high, the electronic devices it uses can be smaller, run faster, and be more reliable. It can also operate at higher temperatures, voltages, and frequencies than other semiconductors.
“Silicon carbide (SiC) is a semiconductor compound composed of silicon (Si) and carbon (C) and belongs to the wide bandgap (WBG) family of materials.”
The prospects are promising!
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Published on 2023-9-17 18:25
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