Introduction to silicon carbide diodes

Silicon carbide is an inorganic substance with the chemical formula SiC. It is produced by high-temperature smelting of raw materials such as quartz sand, petroleum coke (or coal coke), and sawdust (salt needs to be added when producing green silicon carbide) through a resistance furnace. Silicon carbide also exists in nature as a rare mineral, moissanite.

Among non oxide high-tech refractory materials such as C, N, and B, silicon carbide is the most widely used and economical one, which can be called steel sand or refractory sand.

Silicon carbide based Schottky diodes have high energy efficiency, high power density, small size, and high reliability, which can break the limits of silicon in the field of power electronics technology and become the preferred device for new energy and power electronics.

Silicon carbide has four main application areas, namely: functional ceramics, advanced refractory materials, abrasives, and metallurgical raw materials. Silicon carbide coarse materials can already be supplied in large quantities and cannot be considered high-tech products, while the application of nanoscale silicon carbide powders with extremely high technological content cannot form economies of scale in the short term.

As an abrasive, it can be used to make grinding tools, such as grinding wheels, oilstones, grinding heads, sanding tiles, etc.

⑵ As a metallurgical deoxidizer and high-temperature resistant material.

High purity single crystals can be used to manufacture semiconductors and silicon carbide fibers. Main application: Used for wire cutting of 3-12 inch monocrystalline silicon, polycrystalline silicon, potassium arsenide, quartz crystals, etc. Engineering processing materials for solar photovoltaic industry, semiconductor industry, and piezoelectric crystal industry.

Used in fields such as semiconductors, lightning rods, circuit components, high-temperature applications, ultraviolet detectors, structural materials, astronomy, disc brakes, clutches, diesel particulate filters, filament pyrometers, ceramic films, cutting tools, heating elements, nuclear fuels, jewelry, steel, protective gear, catalyst supports, etc.

Silicon carbide diodes have the advantages of high efficiency, high power, and high frequency, and are mainly used in converters for high-frequency power supplies in heavy-duty motors and industrial equipment.

In new energy vehicles, SiC diodes are mainly used for on-board OBC and ground charging station equipment.

In photovoltaic inverters, SiC diodes are mainly used in the front-end MPPT circuit as boost diodes.

Silicon carbide MOSFET modules have significant advantages in the application of high-power power systems such as photovoltaics, wind power, electric vehicles, and rail transit. The advantages of high voltage, high frequency, and high efficiency of silicon carbide devices can break through the limitations of existing electric vehicle motor designs due to device performance, which is currently the focus of research and development in the field of electric vehicle motors at home and abroad. The hybrid electric vehicle (HEV) and pure electric vehicle (EV) power control unit (PCU) jointly developed by Denso and Toyota use silicon carbide MOSFET modules, reducing the volume ratio to 1/5. The EV motor drive system developed by Mitsubishi uses SiC MOSFET modules, and the power drive module is integrated into the motor, achieving the goals of integration and miniaturization.