A Comparison of SiC-Based Devices for Use as Power Switches

Overview

The document titled "A Comparison of SiC Power Switches for Hi-Rel Defense Applications" is a conference paper authored by Michael S. Mazzola and Jeffrey B. Casady, published in July 2007. It focuses on the evaluation of Silicon Carbide (SiC) power switches, particularly the Vertical Junction Field Effect Transistor (VJFET) and the Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET), for high-reliability defense applications.

The paper highlights the advantages of SiC VJFETs, which combine the high switching speed of Silicon MOSFETs with the voltage and current handling capabilities of Insulated Gate Bipolar Transistors (IGBTs), along with superior thermal properties due to the SiC material. These characteristics make SiC VJFETs suitable for various power electronics applications, including high-temperature motor drives, switch modules, and inverters/converters used in military systems such as shipboard power systems and more electric vehicles.

A key aspect of the paper is the comparison of the performance metrics of SiC VJFETs and SiC MOSFETs, particularly focusing on the figure of merit (FOM) defined by the product of on-resistance (R_on) and total gate charge (Q_g). This FOM is crucial for evaluating the efficiency of FET technologies in switch mode power supply (SMPS) applications. The authors argue that while SiC MOSFETs are often considered the leading technology, the SiC VJFET presents compelling advantages that challenge this conventional wisdom.

The document also discusses the challenges associated with the commercialization of both SiC VJFETs and MOSFETs, noting that preproduction samples are becoming available, which allows for a more informed comparison based on recent literature. The authors emphasize the importance of understanding the true properties of SiC devices and the economic factors that influence their adoption in various applications.

In addition to the technical analysis, the paper provides insights into the backgrounds of the authors, both of whom have extensive experience in SiC device development and power electronics. Dr. Mazzola and Dr. Casady have contributed significantly to the field through numerous publications and patents.

Overall, the document serves as a comprehensive resource for understanding the potential of SiC power switches in high-reliability defense applications, offering a critical perspective on their performance and commercialization challenges.