一种具有三维p型埋层的超高压4H-SiC混合PiN肖特基二极管

• 作 者: 杨帅 张晓东 曹安 雒文瑜 张光磊 彭博 赵晋津
• 出 处: 中南大学学报（英文版）
• 发表日期: 2021年12期
• 关键词: 4H polytype silicon carbide merged PiN Schottky diode power diode three dimensio

现代社会对半导体芯片具有旺盛的需求,而4H型碳化硅(4H-SiC)功率器件是下一代半导体芯片中极具潜力的候选者,可应用于各种电力电子系统.为了提高4H-SiC功率器件的性能,本文提出了一种具有三维(3D)p型埋层(PBL)的超高压(UHV)4H-SiC混合p型/本征/n型(PiN)肖特基(MPS)(3D-PBL MPS)二极管,并进行了数值模拟仿真研究.3D-PBL MPS的静态正向导通特性与没有PBL的传统4H-SiC MPS二极管(PBL-free MPS)的相近.然而,当3D-PBL MPS处于反向阻断状态时,3D PBL可以将峰值电场(Epeak)转移到外延层体内更深的位置,增强器件屏蔽肖特基接触界面处高电场(ES)的能力.因此,3D-PBL MPS在10 kV下的反向漏电流密度仅为PBL-free MPS的0.002％.新型3D-PBL MPS也克服了具有二维PBL的4H-SiC MPS二极管(2D-PBL MPS)的缺点.当器件从反向阻断状态转换到正向导通状态后,3D-PBL MPS的正向导通特性不会退化,这是由于3D PBL具有特殊的耗尽层变化机制.所有器件仿真结果表明,新型UHV 3D-PBL MPS具有出色的器件性能.“,”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 (Epeak) 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 (ES), 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.