New Trends in High Voltage MOSFET Based on Wide Band Gap Materials
Prof. PHILIPPE GODIGNON
At present, most of power devices are based on the very well established Silicon technology, covering a huge market of applications as low as 20 V up to several kV. However, Silicon material properties limit power devices' performances regarding blocking voltage capability, operation temperature and switching frequency. Therefore, new generations of power devices based on Wide Band Gap (WBG) semiconductor materials are mandatory for high efficiency power converters. Silicon Carbide (SiC) is one of the most advanced WBG materials for power devices as far as maturity of their starting material and technological processes are concerned, and thanks to commercial availability of rectifier and switches up to 1.7KV. For higher voltage, the potential of SiC is still higher compared to Si. The GaN most efficient structure is the lateral HEMT, which is limited to breakdown voltage lower than 1.2kV. For higher voltage and power ranges, GaN will not be more efficient than SiC, both in terms of performances and cost. For the longer term, two others WBG materials are emerging for high power. Diamond is the most efficient semiconductor for power devices from the theoretical point of view. On the other hand, Gallium Oxide (β and α-Ga2O3) is a low cost material with electrical properties between diamond and SiC. We will review the potential of all these material to build high voltage power MOSFETs with a more specific insight on the most advanced, SiC.