Wide-bandgap (WBG) power semiconductor devices have become increasingly popular due to their superior characteristics compared to their Si counterparts. However, their fast switching speed and the ability to operate at high frequencies brought new challenges, among which the electromagnetic interference (EMI) is one of the major concerns. Many works investigated the structures of WBG power devices and their switching performance. In some cases, the conductive or radiated EMI was measured. However, the EMI-related topics, including their influence on noise sources, noise propagation paths, EMI reduction techniques, and EMC reliability issues, have not yet been systematically summarized for WBG devices. In this article, the literature on EMI research in power electronics systems with WBG devices is reviewed. Characteristics of WBG devices as EMI noise sources are reviewed. EMI propagation paths, near-field coupling, and radiated EMI are surveyed. EMI reduction techniques are categorized and reviewed. Specifically, the EMI-related reliability issues are discussed, and solutions and guidelines are presented.

A Survey of EMI Research in Power Electronics Systems With Wide-Bandgap Semiconductor Devices

This paper overviews the silicon carbide (SiC) technology. The focus is on the benefits of SiC based power electronics for converters and systems, as well as their ability in enabling new applications. The challenges and research trends on the design and application of SiC power electronics are also discussed

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Overview of Silicon Carbide Technology: Device, Converter, System, and Application

SiC devices are promising for outperforming Si counterparts in high-frequency applications due to its superior material properties. Conventional wirebonded packaging scheme has been one of the most preferred package structures for power modules. However, the technique limits the performance of a SiC power module due to parasitic inductance and heat dissipation issues that are inherent with aluminum wires. In this article, low parasitic inductance and high-efficient cooling interconnection techniques for Si power modules, which are the foundation of packaging methods of SiC ones, are reviewed first. Then, attempts on developing packaging techniques for SiC power modules are thoroughly overviewed. Finally, scientific challenges in the packaging of SiC power module are summarized.

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Review of Packaging Schemes for Power Module

Silicon carbide (SiC) power modules are promising for high-power applications because of the high breakdown voltage, high operation temperature, low ON-resistance, and fast switching speed However, the large parasitic inductance in existing package designs results in compromised performance, ie, long blanking time in the desaturation protection scheme and large overvoltage spikes during the switching transient Consequently, the benefits of SiC devices are often not fully utilized in practical applications This paper deals with these two issues and aims at improving the electrical performance of the existing SiC module package Specifically, a package design with Kelvin drain-to-source connection is first proposed to minimize the blanking time More than 99% reduction of blanking time is achieved experimentally compared to the conventional package design Second, a low parasitic inductance package with double-side cooling is proposed to allow the fast switching speed of SiC devices without sacrificing the thermal performance A power loop inductance of 163 nH is realized from Q3D simulation Verified by the experiment, more than 60% reduction of power loop inductance is achieved in comparison to a previously designed baseline module At 0- $\Omega $ external gate resistance, the turn-off voltage spike is less than 9% of the dc-link voltage under the rated load condition

Electrical Performance Advancement in SiC Power Module Package Design With Kelvin Drain Connection and Low Parasitic Inductance

New packaging solutions and power module structures are required to fully utilize the benefits of emerging commercially available wide bandgap semiconductor devices. Conventional packaging solutions for power levels of a few kilowatt are bulky, meaning important gate driver and measurement circuitry are not properly integrated. This paper presents a fast-switching integrated power module based on gallium nitride enhancement-mode high-electron-mobility transistors, which is easier to manufacture compared with other hybrid structures. The structure of the proposed power module is presented, and the design of its gate driver circuit and board layout structure is discussed. The thermal characteristics of the designed power module are evaluated using COMSOL Multiphysics. An ANSYS Q3D Extractor is used to extract the parasitics of the designed power module, and is included in simulation models of various complexities. The simulation model includes the SPICE model of the gallium nitride devices, and parasitics of components are included by experimentally characterizing them up to 2 GHz. Finally, the designed power module is tested experimentally, and its switching characteristics cohere with the results of the simulation model. The experimental results show a maximum achieved switching transient of 64 V/ns and verify the power loop inductance of 2.65 nH.

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A Fast-Switching Integrated Full-Bridge Power Module Based on GaN eHEMT Devices

A critical issue with the SiC UMOSFET is the need to develop a shielding structure for the gate oxide at the trench bottom without any increase in the JFET resistance. This study describes our new UMOSFET named IE-UMOSFET, which we developed to cope with this trade-off. A simulation showed that a low on-resistance is accompanied by an extremely low gate oxide field even with a negative gate voltage. The low RonA was sustained as Vth increases. The RonA values at V g =25 V (E ox =3.2 MV/cm) and VG=20V (E ox =2.5 MV/cm), respectively, for the 3mm × 3mm device were 2.4 and 2.8 mΩcm2 with a lowest Vth of 2.4 V, and 3.1 and 4.4 mΩcm2 with a high Vth of 5.9 V.

1200 V SiC IE-UMOSFET with low on-resistance and high threshold voltage

A novel packaging structure for high-speed switching silicon carbide (SiC) power modules has been proposed based on antiparalleled phase leg units. A prototype 1200 V-360 A SiC power module is developed using SiC-MOSFETs and SiC-SBDs and the very low parasitic inductance of 3.8 nH has been achieved. The experimental results show that the ultra-fast switching can be available owing to the very low parasitic inductance.

Ultra low inductance power module for fast switching SiC power devices

The effect of a gate trench bottom p+ region (BPR) on the dynamic characteristics of 4H-SiC double-trench MOSFETs was investigated. Although employing a BPR led to an improved trade-off in the static characteristics, a BPR adversely affected the switching characteristics in spite of a reduction in the Miller capacitance compared to the case without a BPR. Simulation analysis revealed that a resistance between a BPR and a source electrode led to an increase in the switching loss. We have found reduction of the resistance is insufficient in order to provide benefits from the BPR. Hence, it is necessary to improve layouts of contacts of the BPR to the source electrode.

Role of Trench Bottom Shielding Region on Switching Characteristics of 4H-SiC Double-Trench Mosfets

This super-junction silicon carbide semiconductor device includes a first conductive type silicon carbide semiconductor substrate (1), a first conductive type first semiconductor layer (2), a parallel pn region (33) in which a first conductive type first column region (31) for epitaxial growth and a second conductive type second column region (30) for ion implantation are arranged alternately in series, a second conductive type second semiconductor layer (16), a first conductive type first semiconductor region (17), a trench (23), a gate electrode (20) that is provided inside the trench (23) via a gate insulating film (19), and a first electrode (22). The first column region has an impurity concentration of 1.1×1016/cm3 to 5.0×1016/cm3.

Kyogoku Shinya

Papers

1200 V SiC IE-UMOSFET with low on-resistance and high threshold voltage

Ultra low inductance power module for fast switching SiC power devices

Role of Trench Bottom Shielding Region on Switching Characteristics of 4H-SiC Double-Trench Mosfets

Super-junction silicon carbide semiconductor device and method for manufacturing super-junction silicon carbide semiconductor device