Silicon carbide power mosfets have become an increasingly popular component in electronics circuit designs, offering numerous advantages over their silicon counterparts.
While this new technology was initially slow to take hold, its adoption is gradually growing for several reasons. Key attributes include:.
High Voltage Breakdown
Silicon carbide (SiC) MOSFETs and IGBTs are considerably more energy efficient than their silicon counterparts and provide various advantages for high-power applications. SiC devices boast faster switching speeds while being suitable for higher temperature environments, as well as reduced conduction loss to help minimize power losses in systems.
SiC metal-oxide-semiconductor field-effect transistor (MOSFET) is a semiconductor device comprised of three main layers: source, gate and drain. They are connected by an electric field induced when powering on. SiC MOSFETs offer wide temperature tolerance with high breakdown voltage making them a good option for high voltage power devices.
Unipolar SiC power MOSFET performance is limited by two key parameters – breakdown voltage and on-resistance. To increase breakdown voltage, the n-layer resistance (drift layer or voltage blocking layer) must become less resistive – this can be accomplished using minority carrier injection from the p region into the thick n layer which allows both electrons and holes to contribute current through its drift layer.
This process is known as avalanche breakdown. Unfortunately, its critical electric field — which determines its breakdown voltage — can be affected by crystal orientation and hole-initiated carrier multiplication processes; to improve this type of breakdown further requires either hole- or electron-initiated carrier multiplication processes to take place concurrently.
High Current Density
SiC power MOSFETs outshone silicon MOSFETs by offering higher current density with reduced on-resistance and switching losses, enabling reduced power loss when applied in applications like on-board chargers, DC/DC converters and photovoltaic inverters on hybrid electric vehicles with system voltages exceeding 800 V.
Unipolar SiC power mosfets operate at significantly higher temperatures than their silicon counterparts, leading to significantly greater current density and reduced on resistance, along with faster switching speeds that help minimize conduction losses, for greater system efficiency.
SiC pn junctions possess intrinsic carrier concentration levels which are more than 10 orders of magnitude lower than those found in silicon, thus decreasing self-heating and increasing reliability. Furthermore, their wide bandgap allows leakage current density to be decreased significantly, further decreasing parasitic effects and overall power loss.
Implementing a non-node contact method and thinner gate oxide layer enabled us to produce a 2 kV, 5 A 4-H SiC MOSFET power diMOSFET with increased blocking voltage and reduced specific on resistance resulting in significant increases in its figure of merit score. This high performance SiC MOSFET can be found in solar inverters, energy storage technologies such as batteries and server datacenters used for AI processing of big data processing.
High Temperature Operation
Silicon carbide power MOSFETs boast superior blocking voltage and current handling capacities compared to their silicon counterparts, making them suitable for applications involving higher temperatures where thermal runaway may be an issue.
SiC MOSFETs and IGBTs boast lower RDS (on) figures that vary less with temperature, enabling higher switching frequencies for quicker motor control in applications like machine tools and automated manufacturing facilities – providing more productivity and precision than their silicon counterparts.
silicon carbide’s low thermal expansion coefficient makes it an excellent material choice for large astronomical telescopes such as Herschel Space Telescope mirrors. Furthermore, due to its hard and rigid qualities, silicon carbide makes an excellent material choice for spacecraft subsystem components that must withstand high levels of transients without warping or bending under stress.
Silicon carbide’s thermal conductivity is about double that of silicon, so it can be cooled at significantly lower temperatures without additional cooling systems being necessary – thus saving both cost and system size. Furthermore, higher operating temperatures allow devices to perform efficiently with increased reliability in high power applications.
Low Switching Losses
Silicon carbide power mosfets offer lower on-resistance and switching losses compared to traditional Si IGBTs, making them suitable for hard and resonant switching topologies such as LLC and ZVS. Furthermore, their higher switching frequencies enable smaller circuit sizes and increased power density.
Silicon carbide power MOSFETs offer many advantages that make them attractive in many applications, including replacing IGBTs in resonant converters that control high-speed servo motors used for automated manufacturing with them, eliminating large heat sinks while increasing system efficiency and decreasing power losses. Their higher operating temperatures and superior thermal conductivity also reduce system power losses.
As they use drain-source Schottky barrier diodes to rapidly reach an off state at turn-off, these devices offer fast recovery times on turn-off. This contrasts with IGBTs which may take much longer for tail current to dissipate into an off state.
Silicon carbide power mosfets’ lower switching losses contribute to greater energy efficiency, lower carbon footprint and improved reliability, more compact circuit design, lower component costs and reduced component count – making silicon carbide an excellent choice for high-speed applications such as DC/DC converters and inverters in hybrid electric vehicles – they can handle voltages up to 1,200 V in both packaged and bare die versions of these devices.
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