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

Abstract

In this paper, 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 μm and 30 μm respectively, and with different termination structures, in order to demonstrate the wide JTE dose tolerance of CD-JTE. Three different doses, 1.7×10 13 cm -2 , 2.2×10 13 cm -2 , and 2.8×10 13 cm -2 , were used for the critical JTE implantation. The measured breakdown voltages (BV) of the diodes with all termination structures and JTE doses were compared with simulation predictions. Electroluminescence (EL) at the breakdown voltage was recorded and used to locate the peak electrical field. The test results matched well with simulation. As a result of the effectiveness and robustness of the CD-JTE, the best achieved BVs from the diodes on the 11 μm and 30 μm epi-layers were 1850 V and 4800 V, respectively.

Geometrical effects in JTE rings termination for 4H-SiC medium-voltage devices

“…However, compared with the published results [7,11], the leakage current in our fabricated device is slightly higher, which reaches 30 nA with an applied voltage of 2300 V, as shown in figure 8. It is believed that the NO annealing process could introduce a positive fixed charge into the SiO 2 /SiC interface [22].…”

“…Kimoto's group also provided a SM-JTE structure [8,9], which has a wider IDW when it is utilized for 4H-SiC ultra-high voltage devices. Recently, counter-doped JTE, which combined JTE implantation and local etching process, was also presented [10,11]. Compared with the structure schematics above, JTE plus assistant outer rings termination (JTE rings) is the original implemented structure, proposed by Kozo et al [12].…”

Experimental Study of High Performance 4H-SiC Floating Junction JBS Diodes

“…This choice mainly arises from two aspects. 1) Compared with double-zone JTE, step-double-zone-JTE and counter-doped JTE, the fabrication process of GA-JTE-OR is compatible with our FJ_JBS fabrication process, where the GA parts can be fabricated with the main junction in the active region and only one additional implantation process is needed to form the JTE and OR parts [21]- [23].…”

Optimal impurity distribution model and experimental verification of variation of lateral doping termination

“…Therefore, VLD termination is widely used in the high-voltage power devices, and its optimization methods have been widely concerned by the industry. [10][11][12][13][14][15][16][17][18][19] In recent years, to improve the blocking ability and reliability of VLD termination, a feasible idea is to use a hybrid VLD termination. Balestra et al proposed a VLD termination structure using diamond-like carbon (DLC) passivation, [14] which reduces the charge effect of the passivation layer in the VLD termination region and enhances the reliability of the termination.…”