Demonstration of a 10-kV Class Waffle-Substrate n-Channel IGBT in 4H-SiC

The silicon carbide (SiC) waffle-substrate n‑channel Insulated Gate Bipolar Transistor (IGBT) is a vertical IGBT designed to operate at blocking voltages below about 15 kV. At these voltages the drift and anode layers are too thin to allow complete removal of the n+ substrate. Instead, a waffle pattern is etched through the substrate to expose the buried anode layer while preserving the structural integrity of the wafer. Feasibility of this approach is demonstrated by fabricating a 10-kV class n-channel IGBT with a differential specific‑on resistance of 160 mΩ-cm2.