Design of a 10kV, 6H-Silicon Carbide Power MOSFET with Low Power Dissipation

Abstract

It is increasingly recognized that semiconductor based electronics that can function at ambient temperatures higher than 150oC without external cooling could greatly benefit a variety of important applications, especially in the automotive, aerospace, and energy production industries. The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in lowpower transistor application until the ambient temperature exceeds approximately 300oC, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog very large scale integrated circuits in this temperature range. However, practical operation of silicon power devices at ambient temperature above 200oC appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and highpower operation will necessarily be realized using wide bandgap devices, once the technology for realizing these devices become sufficiently developed that they become widely available. The present work aims at the design of a 10kV high power 6H-SiC MOSFET with a power dissipation (PD) that can be set at the limits much lower than 800W which is the maximum permissible limit for a high power SiC MOSFET. It is found that PD values with 10kV breakdown voltages in 6H-SiC Power MOSFET’s can be kept at reasonably low values of PD ranging from 0.03W to 200W by doping the drift region to values of 5´1015/CC to 5 ´1013/CC respectively. PD calculations used here set Ronsp (Specific on resistance) equal to RD (Specific on resistance of the drift region) as is the case with SiC power MOSFET’s with high breakdown voltages.