Grayscale Junction Termination for High-Voltage SiC Devices
In silicon carbide devices used above around 2.4 kV, effective anode edge termination usually requires a high-resolution floating guard ring implant or multiple lithography/implant cycles to effect a multi-zone junction termination extension. In general the goal is to produce a smoothly tapered field profile to prevent high-voltage field-crowding that causes premature breakdown at the edge of the high voltage electrode. Using a much simpler grayscale photolithographic technique and a single termination implant, we directly produce the desired tapered doping profile. The effectiveness of this termination is shown by the near-ideal (6.1 kV) breakdown measured in PiN diodes made with a 38 µm intrinsic layer. The simple method is applicable to the fabrication of many high-voltage devices.
Amador Pérez-Tomás, Philippe Godignon, Miquel Vellvehí and Pierre Brosselard
E. A. Imhoff et al., "Grayscale Junction Termination for High-Voltage SiC Devices", Materials Science Forum, Vols. 615-617, pp. 691-694, 2009