Voltage-Driven Reverse Recovery in Semiconductor Devices: A Diffusion Capacitance Perspective and Behavioral Model for SiC MOSFETs

Reverse recovery is a crucial aspect of switching losses in semiconductor devices. Traditionally, the reverse recovery process is described as the sweeping out of minority carriers stored in the drift region over time. This paper proposes that the sweeping out of the carriers can be attributed solely to voltage variation, rather than to the passage of time, representing a capacitive effect termed diffusion capacitance. The rationality for using diffusion capacitance to describe the reverse recovery current is explained, along with a review of the mechanism of diffusion capacitance. A linearized behavioral model for SiC MOSFETs based on the proposed perspective is developed and analytically solved. This model is subsequently validated through experimental tests conducted on a 1.2 kV commercial SiC MOSFET, with the results demonstrating strong agreement. Finally, the superiority of the model is demonstrated and the potential of the proposed model for analyzing switching losses is discussed.