A Comparative Study of Silicon Carbide Merged PiN Schottky Diodes with Electrical-Thermal Coupled Considerations

Abstract

A comparative study of surge current reliability of 1200 V/5 A 4H-SiC (silicon carbide) MPS (Merged PiN Schottky) diodes with different technologies is presented. The influences of device designs in terms of electrical and thermal aspects on the forward conduction performance and surge current capability were studied. Device forward characteristics were simulated and measured. Standard single-pulse surge current tests and thermal impedance measurements were carried to show their surge capability and thermal design differences. An advanced thermal RC (thermal resistance-capacitance) model, with the consideration of current distribution non-uniformity effects, is proposed to accurately calculate the device junction temperature during surge events. It was found that a thinner substrate and a hexagonal layout design are beneficial to the improvement of the bipolar conduction performance in high current mode, as well as the surge current capability. The thinner substrate design also has advantages on thermal aspects, as it presents the lowest thermal resistance. The calculated failure temperature during the surge tests is consistent with the aluminum melting phenomenon, which is regarded as the failure mechanism. It was demonstrated that, for a SiC MPS diode, higher bipolar conduction performance is conducive to restraining the joule heat, and a lower thermal resistance design is able to accelerate the heat dissipation and limit the junction temperature during surge events. In this way, the MPS diode using a thinner substrate and advanced layout design technology is able to achieve 60% higher surge current density capability compared to the other technologies.

Transient Electro-Thermal Coupled Modeling of Three-Phase Power MOSFET Inverter during Load Cycles

“…Power semiconductors/modules inside inverters are the most crucial devices controlling the power conversion efficiency. In response to the urgent need for high-performance power conversion applications, the power semiconductor industry has recently seen rapid technological developments, such as insulated-gate bipolar transistors (IGBTs) [ 1 , 2 ], metal-oxide semiconductor field effect transistors (MOSFETs) [ 3 , 4 ], and even wide bandgap (WBG) silicon carbide (SiC) [ 5 , 6 ] and gallium nitride (GaN) power devices [ 7 ]. In contrast to IGBTs, MOSFETs comprise a number of advantageous features, such as a higher switching frequency and lower switching loss; accordingly, they have been used in a wide range of industrial applications, such as converters and inverters.…”

Special Issue: Silicon Carbide: From Fundamentals to Applications

“…The authors have shown that a specially created design, which is described in detail in this article, allows well dissipation of the heat generated during the operation of the diode, and significantly increases the throughput of pulsed currents of diodes of this type. In Reference [ 1 ], it was demonstrated that high bipolar electrical conductivity causes overheating of the device, and the design of the device with a low thermal resistance can accelerate heat removal and limit the junction temperature during voltage surges. The authors cite in Reference [ 1 ] a description of the MPS diode design which can provide 60% higher pulse current density compared to other technologies.…”

“…In Reference [ 1 ], it was demonstrated that high bipolar electrical conductivity causes overheating of the device, and the design of the device with a low thermal resistance can accelerate heat removal and limit the junction temperature during voltage surges. The authors cite in Reference [ 1 ] a description of the MPS diode design which can provide 60% higher pulse current density compared to other technologies.…”

“…Below, we provide a brief summary of the works included in the collection. Three of the total seven articles [1][2][3] are devoted to the technology of creating electronic devices based on silicon carbide single crystals. So, in Reference [1], a comparative study of the electrical and thermal parameters of three commercial Schottky diodes 1200 V/5 A MPS (Merged PiN Schottky) made on 4H-SiC was carried out.…”

“…Three of the total seven articles [1][2][3] are devoted to the technology of creating electronic devices based on silicon carbide single crystals. So, in Reference [1], a comparative study of the electrical and thermal parameters of three commercial Schottky diodes 1200 V/5 A MPS (Merged PiN Schottky) made on 4H-SiC was carried out. The authors demonstrated that to create high-quality SiC-based diodes, an optimal combination of good electrical forward conductivity with good heat dissipation is necessary.…”