Silicon carbide mosfets (MOSFETs) are an increasingly prevalent component in power electronic designs. These wide band gap power semiconductors boast many advantages over silicon devices, including reduced switching losses and decreased heat dissipation.
These exceptional characteristics make these drives ideal for high-temperature applications such as electric vehicle charging stations, renewable energy systems, UPS units and motor drives. Read on to discover more of these outstanding benefits.
High Breakdown Voltage
Silicon carbide MOSFETs feature an order of magnitude higher breakdown electric field than traditional silicon devices, enabling them to function at higher temperatures while reaching greater switching power levels with reduced conduction and switching losses. Their higher breakdown voltage also enables thinner and more highly doped blocking layers with increased majority carriers for lower specific on-resistance (Ron,sp).
Silicon carbide mosfets feature high breakdown voltages that enable them to function at much higher temperatures than standard silicon devices without increasing leakage current or damaging gate oxide, helping reduce power loss while improving reliability in harsh operating conditions. This leads to reduced overall power loss as well as enhanced reliability under difficult operating conditions.
Silicon carbide stands out as an outstanding chemical resistance and wear resistance material, which makes it perfect for applications like high-temperature power supplies and voltage converters where harsh environmental conditions could potentially cause corrosion damage to their device.
Silicon carbide’s superior thermal performance enables higher operating frequencies that increase power density and efficiency for applications like industrial motor drives, uninterruptible power supplies, renewable energy systems, charging stations for electric vehicles and IT data centers – these benefits make this technology a game-changer in power electronics industry.
Silicon Carbide is a semiconductor material, meaning that its structure contains silicon and carbon atoms. With a melting point of 2800 degC and chemical inert properties that make it radiologically inert, this substance boasts outstanding radiation resistance qualities.
weEn’s CoolSiC discrete products are perfectly suited for hard and resonant switching topologies such as LLC and ZVS and can be driven using standard drivers just like IGBTs or CoolMOSTM C7s. Their robust designs feature state-of-the-art trench designs for improved gate oxide reliability as well as best-in-class switching and conduction losses with Vth = 4 V – giving these devices a distinct advantage over traditional silicon technologies, providing maximum efficiency and lifetime reliability for users.
High Efficiency
Silicon carbide may not be familiar, but it plays a critical role in semiconductor devices. Manufactured at high temperatures from silicon dioxide and carbon, silicon carbide is used to produce blanks needed for electronic components like diodes and MOSFETs.
Industrial motor drives, AC/DC inverters/converters, uninterruptible power supplies and solar photovoltaic (PV) systems all place high demands on performance of standard silicon transistors. As such, newer transistor architectures that offer greater energy efficiency, reduced energy consumption and lower total cost of ownership over the lifespan of power systems have emerged to meet them.
Power SiC MOSFETs share the same basic structure as traditional metal-oxide semiconductor field-effect transistors (MOSFETs), with three terminals: power source, drain and gate connected via control gate to an outside control circuit. Furthermore, these MOSFETs have higher voltage breakdown strengths allowing them to withstand higher transient voltages without de-rating, making them suitable for systems utilizing capacitive loads or uninterruptible power supplies.
SiC MOSFETs bring power electronics a significant efficiency advantage over silicon-based devices due to a combination of factors, including faster switching speeds and less parasitic capacitance. A higher switching frequency enables more current to be switched in an allocated period, meaning smaller inductive and capacitive components can be utilized.
Silicon carbide’s wider bandgap allows more current to flow through at a given temperature, thereby improving efficiency by lowering power losses and increasing efficiency. Furthermore, their smaller on-state resistance compared to silicon power MOSFETs permits for faster switching speeds without increasing power losses.
Reliability has also seen dramatic improvements since Toshiba first-generation SiC MOSFETs were introduced. One key problem with original devices was that when turning them on, their PN diode would energize, leading to changes in on resistance which degrade reliability of device. Toshiba’s second generation devices address this problem by including a Schottky barrier diode (SBD) which prevents its activation when turning it on and changes on resistance can occur resulting in changes that degrade device reliability.
Lower On-Resistance
Silicon carbide mosfets offer circuit designers several advantages over traditional silicon transistor mosfets due to their lower on-resistance. This allows for higher switching frequencies with the same current, leading to increased efficiency that leads to smaller components and lower losses overall. Furthermore, these SiC mosfets operate over a wider temperature range, further reducing total system losses while simultaneously increasing power density and energy conversion efficiency.
Silicon carbide’s critical breakdown voltage is over 10 times higher than that of silicon, creating thinner drift layers and a smaller depletion region. Furthermore, due to its wider bandgap characteristics, electrons move through more freely between drain and source terminals, resulting in lower on-state resistance resistance.
Silicon carbide’s greater electron mobility compared to silicon allows more electrons to pass through each gate activation, leading to much lower on-resistance values that may even reach less than one milliohm at its highest operating temperature.
UnitedSiC (now Qorvo) recently unveiled the industry’s lowest on-resistance SiC FET: 750V/6m in a standard discrete package – which is half that of its closest competitor! This level of on-resistance allows high voltage applications that would typically require IGBTs or standard power MOSFETs to be significantly derated without incurring extra costs.
However, it should be remembered that the on-resistance of any power device depends on many variables including die surface area and percentage inactive areas such as termination regions around edges or gate pads for contact – this can skew calculations if quoted without regard for these parameters.
SiC MOSFETs that employ IGBT drivers require typically 15-18 V for optimal on-resistance; however, lower voltage drivers are also possible to further decrease on-resistance levels.
Silicon carbide’s combination of key performance characteristics make it an ideal material for high-voltage power applications, including hard-switching topologies in LLC and ZVS converters; inverters for electric vehicles, industrial power supplies and circuit protection; renewable energy generation and data center power applications. Wolfspeed offers an extensive portfolio of 1000 V silicon carbide power devices optimized for fast switching with maximum efficiency, perfect for applications requiring low on resistance, ultra low output capacitance and low source inductance to provide the optimal balance of power loss/conduction loss ratios.
Higher Switching Frequency
Silicon carbide MOSFETs typically feature higher switching frequencies than their silicon counterparts due to reduced on-resistance and switching losses, higher electron mobility (which allows electrons to travel through their channel more quickly), smaller inductive/capacitive components being used, which leads to decreased system size and costs.
SiC is also known for having a wider bandgap, making for a thinner depletion region, making electron movement between gate and source terminals simpler, further lowering on-resistance and increasing voltage blocking capability, making SiC MOSFETs suitable for high voltage power applications.
Silicon Carbide MOSFETs offer many advantages that make them suitable for industrial and power electronics applications. They can replace silicon transistors in power converters and inverters to increase efficiency and power density, and be used as power supply components in applications like electric vehicles (EVs) or renewable energy systems.
SiC MOSFETs’ lower on-resistance can extend their operational lifetime by creating a larger switching window and thus decreasing risk of thermal runaway. However, designers must remember that SiC MOSFET power dissipation increases with temperature; to optimize dead time and power-dissipation regions for maximum performance.
SiC MOSFETs’ high switching frequency makes them particularly sensitive to parasitic parameters in their device package, such as stray inductance and capacitance that cause overvoltage at their terminals. To combat this problem, designers can employ wire-bondless technology techniques that minimize these inductive components.
SiC MOSFETs feature higher switching frequencies that enable smaller passive components in power supplies to improve system reliability and reduce solution costs, which is especially advantageous in high-power applications like electric vehicle inverters and wind and solar energy systems.