In recent years, the structure design and fabrication technology of SiC power devices are becoming more and more perfect, which is close to the theoretical limit determined by the material characteristics of SiC power devices. The potential of improving the performance of devices and systems relying on the continuous improvement of SiC power devices is very limited. In this paper, the development status and market prospects of SiC power semiconductor devices are introduced firstly. Secondly, the existing problems in the development of SiC power semiconductor devices are described. Finally, the breakthroughs of SiC power semiconductor devices are introduced.
Development Status of SiC Power Semiconductor Device Technology
Silicon carbide power diode
There are three types of silicon carbide power diodes: Schottky diode (SBD), PiN diode and barrier controlled Schottky diode (JBS). Because of the existence of Schottky barrier, SBD has a lower junction barrier height. Therefore, SBD has the advantage of low forward voltage. The emergence of SiC SBD has increased the application range of SBD from 250 V to 1200 V. At the same time, its high temperature characteristics are good. From room temperature to 175 ~C defined by the shell, the reverse leakage current almost does not increase. In the application field of rectifiers above 3 kV, SiC PiN and SiC JBS diodes have attracted much attention due to their higher breakdown voltage, faster switching speed, smaller size and lighter weight than Si rectifiers.
Unipolar power transistor, silicon carbide power MOSFET device
Silicon power MOSFET devices have ideal gate resistance, high-speed switching performance, low on-resistance and high stability. In the field of power devices below 300V, it is the preferred device. It has been reported that SiC MOSFET with blocking voltage of 10 kV has been successfully developed. Researchers believe that silicon carbide MOSFET devices will occupy a dominant position in the field of 3-5 kV. Despite many difficulties, significant progress has been made in the research and development of silicon carbide MOSFET devices with high voltage and current capabilities.
In addition, it has been reported that the reliability of silicon carbide MOSFET gate oxide layer has been significantly improved. It has good reliability at 350 C. These results indicate that gate oxide layer will hopefully no longer be a significant problem in silicon carbide MOSFET.
Silicon carbide insulated gate bipolar transistors (SiC BJT, SiC IGBT)
And SiC Thyristor
Recently, silicon carbide P-type IGBT device with blocking voltage of 12 kV has been reported, and it has good forward current capability. The on-resistance of silicon carbide IGBT devices can be compared with that of unipolar silicon carbide power devices. Compared with Si bipolar transistors, SiC bipolar transistors have 20-50 times lower switching losses and lower on-off voltage drop. SiC BJT is mainly divided into epitaxy emitter and ion implantation emitter. The typical current gain is between 10 and 50.
About silicon carbide thyristor, it has been reported that the 1 square centimeter thyristor chip has a blocking voltage of 5 kV, a current of 100A (voltage 4.1V) at room temperature, and a turn-on and turn-off time of tens to hundreds of nanoseconds.
SiC power devices have broad market prospects, reaching US$436 million by 2020, with a compound annual growth rate of 22%.
Prediction: By 2025, the SiC MOSFET market will exceed US$300 million and become the second largest SiC discrete power element after SiC Schottky Diode; SiC FETs and BJTs products are trusted by the market, but mostly used in professional or niche products, which is much smaller than SiC MOSFET market; hybrid SiC power formed by combining SiC diodes with Si IGBT Module, sales are expected to exceed $1 billion in 2025.
SIC Road of Power Semiconductor Expects Breakthrough
The development history of power electronic devices can be roughly divided into three major stages: silicon thyristor (thyristor), IGBT (insulated gate bipolar transistor) and silicon carbide (SiC) high power semiconductor devices. The development of thyristors has been nearly 60 years, and the mature technology has been widely used. It can be used for reference to predict silicon carbide power devices. When IGBT came into being, it differed greatly from the parameters of thyristors. When thyristors were able to achieve 2-3KV and 2-3KA, IGBT only had a current of over 100 and a voltage of over 1000. In the past twenty years, IGBT has developed rapidly from the first generation to the sixth generation. Voltage and current have kept pace with thyristors, showing the superior performance of IGBT.
IGBT, which is capable of thyristor, can't do all-round and IGBT can't. In a considerable field of application, IGBT is the best because of its irreplaceable superiority. But the thyristor still holds its own large position with its relatively high cost performance ratio. Advances in silicon carbide materials technology have made it possible for some silicon carbide power devices to be used in practice.