| Popis: |
The continuing electrification and digitization in the 21st century demands more and more electrical energy. Thus, efficient and reliable energy harvesting from renewable energy resources becomes a crucial milestone to maintain our global ecosystem and our natural habitat. Power semiconductor devices, being key components for the development of efficient electrical distribution, motion, and drive systems, play a major role in the achievement of this milestone from a technological perspective. For the last few decades the fabrication of these power semiconductors was exclusively based on Si substrate material. New wide bandgap materials such as silicon carbide are emerging, exhibiting material properties bringing several benefits for the utilization of power devices. Since 2001, SiC power diodes and, later, power MOSFETs have become commercially available. A power MOSFET is a voltage controlled current source, which has a currentblocking and a current-conductive state equivalent to an electrical switch. The use of vertical SiC power MOSFETs (VDMOSFETs) allows to further increase the power density and efficiency of power electronics systems. This work focuses on electrical current-voltage (I-V) and capacitance-voltage (C-V) characterization of fast-switching SiC power VDMOSFETs based on corresponding lumped I-V and C-V electrical equivalent models. In particular, the distributed behavior of the input capacitance and input resistance are explained, the differences between drain-source and gate-source dependent C-V characterization are demonstrated, and the two-voltage dependent C-V characterization based on ramp-rate measurements is shown. A new methodology is presented for the extraction of the channel and drift resistance components from the total on-state resistance based on the extracted gate capacitance characteristics. Furthermore, these I-V and C-V characteristics of a VDMOSFET are used to investigate the accuracy of turn-on and turn-off switching transients and the estimation of the corresponding switching loss energies. Overall, this work can be used as a guideline for electrical characterization of power VDMOSFETs and as reference for the trade-off between VDMOSFET modeling complexity and simulation accuracy. |
