kV Silicon Carbide Power Research Articles

Temperature Dependence of 55 nm Gate Oxide, 2.3 kV SiC Power JBSFETs With Linear, Hexagonal, and Octagonal Cell Layouts

The electrical characteristics of 2.3-kV 4H-SiC power Junction Barrier Schottky Field-Effect Transistors (JBSFETs) fabricated with 55-nm gate oxide thickness are reported as a function of temperature for the first time. The behavior of three cell topologies (linear, hexagonal, and octagonal) is compared. Excellent JBSFET characteristics are demonstrated up to 150 °C. The ON-resistance was found to increase by 45% from 25 °C to 150 °C for the linear and hexagonal cell layouts, which is much less than the 100% increase previously reported for silicon carbide (SiC) power MOSFETs. The threshold voltage decreases with temperature but remains above 1.2 V even at 150 °C for all cases. The third-quadrant current flow via the integrated JBS diode is confirmed to suppress body diode conduction at all temperatures. The leakage current remains below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~\mu \text{A}$ </tex-math></inline-formula> even at 150 °C despite the presence of the Schottky contact in the JBSFET structure due to optimum JBS diode design. The octagonal cell topology is shown to exhibit the best figures of merit (FOMs) FOM[ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ \mathrm{R}_{ \mathrm{\scriptscriptstyle ON}}{}^{\ast } \mathrm{C}_{ \mathrm{\scriptscriptstyle GD}}$ </tex-math></inline-formula> ] and FOM[ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$ \mathrm{R}_{ \mathrm{\scriptscriptstyle ON}}{}^{\ast } \mathrm{ Q}_{ \mathrm{\scriptscriptstyle GD}}$ </tex-math></inline-formula> ] even at elevated temperatures. The observed device behavior is explained using device analytical modeling. The analytical modeling reveals that the reduced rate of increase in ON-resistance with temperature for the 2.3-kV SiC JBSFETs is due to the relatively large source contact resistance produced by the lower (900 °C) contact anneal temperature. The lower anneal temperature is required to simultaneously make the Schottky contact for the JBS diode.

Packaging Design of 15 kV SiC Power Devices With High-Voltage Encapsulation

Silicon carbide (SiC) is capable of improving the blocking voltage of power devices. It is essential to package SiC power devices for high-voltage applications. This article proposes a high-voltage packaging method for &#x003E;15-kV SiC power devices by designing an optimized stacked direct bond copper (DBC) substrate with a copper ring and a field-dependent conductivity (FDC) encapsulation using SiC as the filler. The proposed FDC encapsulation is proven as a promising encapsulation as commercial silicone. The partial discharge initial voltage (PDIV) of the demonstrated module using the proposed method can be improved to at least 18.31 kV, which is increased by 163.77&#x0025; compared with the typical 34-mm insulated gate bipolar transistor (IGBT) modules. The maximum voltage rating of the demonstrated module could be enhanced to at least 15 kV with a sufficient protection margin, i.e., 20&#x0025;. It gives guidance to the packaging of &#x003E;15-kV SiC power devices.

Understanding High Temperature Static and Dynamic Characteristics of 1.2 kV SiC Power MOSFETs

High temperature capability of silicon carbide (SiC) power MOSFETs is becoming more important as power electronics faces wider applications in harsh environments. In this paper, comprehensive static and dynamic parameters of 1.2 kV SiC MOSFETs have been measured up to 250°C. The electrical behaviors with the temperature have been analyzed using the basic device physics and analytical models.

High-Temperature Characterization and Comparison of 1.2 kV SiC Power Semiconductor Devices

Focused on high-temperature (200°C) operation, this paper seeks to provide insight into state-of-the-art 1.2 kV silicon carbide (SiC) power semiconductor devices; namely the MOSFET, BJT, SJT, and normally-off JFET. This is accomplished by characterizing and comparing the latest generation of these wide bandgap devices from various manufacturers (Cree, GE, ROHM, Fairchild, GeneSiC, and SemiSouth). To carry out this study, the static and dynamic characterization of each device is performed under increasing temperatures (25–200°C). Accordingly, this paper describes the experimental setup used and the different measurements conducted, which include: threshold voltage, current gain, specific on-resistance, and the turn-on and turn-off switching energies of the devices. The driving method used for each device is also detailed. Key trends and observations are reported in an unbiased manner throughout the paper and summarized in the conclusion.

High-Temperature Characterization and Comparison of 1.2 kV SiC Power Semiconductor Devices

Focused on high-temperature (200 °C) operation, this paper seeks to provide insight into state-of-the-art 1.2 kV Silicon Carbide (SiC) power semiconductor devices; namely the MOSFET, BJT, SJT, and normally-off JFET. This is accomplished by characterizing and comparing the latest generation of these wide bandgap devices from various manufacturers (Cree, GE, Rohm, Fairchild, GeneSiC, and SemiSouth). To carry out this study, the static and dynamic characterization of each device is performed under increasing temperatures (25–200 °C). Accordingly, this paper describes the experimental setup used and the different measurements conducted, which include: threshold voltage, current gain, specific on-resistance, and the turn-on and turn-off switching energies of the devices. The driving method used for each device is also detailed. Key trends and observations are reported in an unbiased manner throughout the paper and summarized in the conclusion.

Comparison of 10 kV 4H-SiC Power MOSFETs and IGBTs for High Frequency Power Conversion

For the first time, large area 10 kV SiC power devices are being produced capable of yielding power modules for high-frequency megawatt power conversion. To this end, the switching performance and power dissipation of silicon carbide (SiC) n-channel IGBTs and MOSFETs are evaluated using numerical simulations software over an extended current range to determine the best device suitable for 10 kV applications. Each device is also optimized for minimal forward voltage drop in the on-state.