An ultrahigh-voltage 4H-SiC merged PiN Schottky diode with three-dimensional p-type buried layers

In the modern society, there is a strong demand for semiconductor chips, and the 4H polytype silicon carbide (4H-SiC) power device is a promising candidate for the next generation semiconductor chip, which can be used in various power electronic systems. In order to improve the performance of the 4H-SiC power device, a novel ultrahigh-voltage (UHV) 4H-SiC merged p-type/intrinsic/n-type (PiN) Schottky (MPS) diode with three-dimensional (3D) p-type buried layers (PBL) (3D-PBL MPS) is proposed and investigated by numerical simulation. The static forward conduction characteristics of the 3D-PBL MPS are similar to those of the conventional 4H-SiC MPS diode without the PBL (PBL-free MPS). However, when the 3D-PBL MPS is in the reverse blocking state, the 3D PBL can transfer the peak electric field (E-peak) into a deeper position in the body of the epitaxial layer, and enhance the ability of the device to shield the high electric field at the Schottky contact interface (E-S), so that the reverse leakage current of the 3D-PBL MPS at 10 kV is only 0.002% of that of the PBL-free MPS. Meanwhile, the novel 3D-PBL MPS has overcome the disadvantage in the 4H-SiC MPS diode with the two-dimensional PBL (2D-PBL MPS), and the forward conduction characteristic of the 3D-PBL MPS will not get degenerated after the device converts from the reverse blocking state to the forward conduction state because of the special depletion layer variation mechanism depending on the 3D PBL. All the simulation results show that the novel UHV 3D-PBL MPS has excellent device performance.

Automated summary

The novel UHV 3D-PBL MPS has outstanding device performance, with the ability to transfer the peak electric field deeper into the epitaxial layer in the reverse blocking state, enhancing the device's ability to shield high electric fields and maintaining forward conduction characteristics.