Etched junction termination extension with floating guard rings and middle rings for ultrahigh-voltage 4H-SiC PiN diodes

A novel termination structure, referred to as etched junction termination extension with floating guard rings and middle rings (E-JFs-MRs), is presented for ultrahigh-voltage (>10kV) 4H-SiC PiN diodes to extend the dose window of the junction termination extension (JTE) and improve the breakdown voltage. The structure is introduced a shallow etching process and middle rings structure to the conventional JTE with floating guard rings(JFs). Numerical device simulations are performed by using Sentaurus
^®
TCAD tools. Compared with the JFs, the JTE dose window (>15kV) of the E-JFs-MRs can be significantly extended by a ratio of 143% for the PiN diode based on the same N type epitaxial layer with 100um thickness and 2×10
¹⁴
cm
^-3
impurity concentration. In the end, the roles of the shallow etching process and middle rings are discussed in detail.