Silicon Carbide: Physics, Manufacturing, and Its Role in Large-Scale Vehicle Electrification

Abstract

Silicon carbide is changing power electronics; it is enabling massive car electrification owing to its far more efficient operation with respect to mainstream silicon in a large variety of energy conversion systems like the main traction inverter of an electric vehicle (EV). Its superior performance depends upon unique properties such as lower switching and conduction losses, safer high-temperature operation and high-voltage capability. Starting briefly with a description of its physics, more detailed information is then given about some key manufacturing steps such as crystal growth and epitaxy. Afterwards, an overview of its inherent defects and how to mitigate them is presented. Finally, a typical EV’s propulsion inverter is shown, proving the technology’s effectiveness in meeting requirements for mass electrification. Foreword: In recent years, SiC has drawn the attention of a growing number of power electronics designers as the material has good prospects for reducing environmental impacts on a global basis. The goal of this paper, based on the author’s contribution to the introduction of the technology at STMicroelectronics, is to show the potential of silicon carbide in enabling massive car electrification. The company’s SiC MOSFETs, tailored to the automotive industry, are enabling visionary EV makers to pave the way for sustainable e-mobility. The intent of this paper is to describe, for a large crowd of readers, how SiC features can accelerate such a transition by quantifying the benefits they bring in terms of improved efficiency in an EV electric powertrain. The paper also has the ambition to highlight the material’s physics and to give an overview of its production processes, starting from the crystal growth for realizing substrates to the main epitaxy techniques. Some space has been devoted to the analysis of the main crystal defects not present in silicon and whose nature poses new challenges in terms of manufacturing yields and screening. Finally, some insights into the market evolution and on the transition to 200 mm wafers are given.