In 1940, Bell Labs discovered that there was a PN junction effect in silicon when it was studying radar detection rectifiers. In 1958, General Electric (GE) of the United States developed the world's first common thyristor for industrial use, marking the birth of power electronics technology.

In recent years, the voice of the Internet of Everything is getting louder and louder, and the electronic development of almost the entire industry is linked to power semiconductor devices, which greatly increases the demand for power semiconductor devices. According to different functions and usage scenarios, power devices are naturally divided into common and uncommon types. Last time we listed common power devices, this time we will talk about uncommon power devices.

1. New GTO device - integrated gate commutated thyristor

There are currently two alternatives to conventional GTOs: high-power IGBT modules, and new GTO-derived devices - integrated gate-commutated IGCT thyristors. IGCT thyristor is a new type of high-power device. Compared with conventional GTO thyristor, it has many excellent characteristics, such as reliable turn-off without snubber circuit, short storage time, strong turn-on capability, and turn-off gate charge. The total power loss of the application system (including all devices and peripheral components such as anode reactors and snubber capacitors, etc.) is low.

2. Pulse power closing switching thyristor

The device is particularly suitable for delivering extremely high peak power (several MW), extremely short duration (several ns) discharge closure switch applications such as: lasers, high intensity lighting, discharge ignition, electromagnetic transmitters and radar modulators Wait. The device can be turned on quickly under a high voltage of several kV, does not require a discharge electrode, has a long service life, is small in size, and has a relatively low price. It is expected to replace the high-voltage ion thyratron, ignition tube, spark, Gap switch or vacuum switch, etc.

The unique structure and process characteristics of the device are: the gate-cathode perimeter is very long and forms a highly interwoven structure, the gate area accounts for 90% of the total chip area, while the cathode area only accounts for 10%; the base hole-electron lifetime Very long, the horizontal distance between gate-cathode is less than one diffusion length. The above two structural features ensure that the device can get 100% application of the cathode area when the device is turned on. In addition, the device's cathode electrode uses a thicker metal layer to withstand transient peak currents.

3. Power Electronic Device (PowerElectronicDevice)

Power Electronic Device (PowerElectronicDevice), also known as power semiconductor device, is used for high-power (usually tens to thousands of amps of current and hundreds of volts or more) electronic devices in power conversion and power control circuits. It can be divided into half-controlled devices, fully-controlled devices and uncontrollable devices, among which thyristors are half-controlled devices, with the highest withstand voltage and current capacity among all devices; power diodes are uncontrollable devices, with simple structure and principle, work Reliable; it can also be divided into voltage-driven devices and current-driven devices, among which GTO and GTR are current-driven devices, and IGBT and power MOSFET are voltage-driven devices.

4.MOS gate controlled thyristor

The MOS gate-controlled thyristor fully utilizes the good on-state characteristics, excellent turn-on and turn-off characteristics of the thyristor, and is expected to have excellent self-turn-off dynamic characteristics, very low on-state voltage drop and high voltage resistance. And there are promising high-voltage and high-power devices in the power system. At present, more than a dozen companies in the world are actively conducting research on MCT. There are three main structures of MOS gated thyristor: MOS field controlled thyristor (MCT), base resistance controlled thyristor (BRT) and emitter switch thyristor (EST). Among them, EST may be the most promising structure among MOS gated thyristors. However, it will take a considerable period of time for this kind of device to become a commercialized practical device and reach the level of replacing GTO.

5. GaAs Diodes

As the switching frequency of the converter continues to increase, the requirements for fast recovery diodes also increase. It is well known that gallium arsenide diodes have superior high-frequency switching characteristics than silicon diodes, but due to process technology and other reasons, gallium arsenide diodes have low withstand voltage, and their practical applications are limited. In order to meet the needs of high-voltage, high-speed, high-efficiency and low-EMI applications, high-voltage gallium arsenide high-frequency rectifier diodes have been successfully developed in Motorola. Compared with silicon fast recovery diodes, this new type of diode has the following notable features: small reverse leakage current changes with temperature, low switching losses, and good reverse recovery characteristics.

At present, the world's power semiconductor devices are mainly provided by three countries and regions: Europe, the United States, and Japan. With their advanced technology, manufacturing process, and leading quality management system, they occupy about 70% of the global market share. With the support of a number of national scientific research programs, China has greatly narrowed the technological gap with the rest of the world, and has made many achievements. Power semiconductors are indispensable upstream devices in many application fields, and will achieve rapid technological and economic growth with the explosion of the industry in the future.