Experimental Study of Counter-Doped Junction Termination Extension for 4H–SiC Power Devices

In this letter, a counter-doped junction termination extension (CD-JTE) structure was experimentally implemented and studied. Two groups of 4H-SiC PiN diodes were fabricated with two n-type drift layer thicknesses of 11 and 30 μm, respectively, and with different termination structures, in order to demonstrate the wide JTE dose tolerance of CD-JTE. Three different doses, 1.7 × 10¹³, 2.2×10¹³, and 2.8×10¹³ cm^-2, were used for the critical JTE implantation. The measured breakdown voltages (BVs) of the diodes with all termination structures and JTE doses were compared with simulation predictions. Electroluminescence at the BV was recorded and used to locate the peak electrical field. The test results matched well with the simulation results. As a result of the effectiveness and robustness of the CD-JTE, the best achieved BVs from the diodes on the 11and 30-μm epilayers were 1850 and 4800 V, respectively.