Tam H. Duong

Recent Advances in High-Voltage, High-Frequency Silicon-Carbide Power Devices

The emergence of high-voltage, high-frequency (HV-HF) silicon-carbide (SiC) power devices is expected to revolutionize commercial and military power distribution and conversion systems. The DARPA wide bandgap semiconductor technology (WEST) high power electronics (HPE) program is spearheading the development of HV-HF SiC power semiconductor technology. In this paper, some of the recent advances in development of HV-HF devices by the HPE program are presented and the circuit performance enabled by these devices is discussed

High-Voltage capacitance measurement system for SiC power MOSFETs

Adequate modeling of a power Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) is dependent on accurate characterization of the inter-electrode capacitances. With the advent of high-voltage silicon carbide (SiC) power MOSFETs, it has become important to develop a measurement system that can perform and record high-voltage capacitance versus voltage measurements on these devices. This paper describes a measurement apparatus that safely and accurately allows high voltage capacitance-voltage (CV) measurements to be performed. The measurements are based on conventional LCR (Inductance (L), Capacitance (C), and Resistance (R)) meter CV techniques but with added circuitry to interface the LCR meter to high voltage bias sources. The effects of the added circuitry are studied theoretically, and the CV measurement accuracy is verified with experimentation. High voltage capacitance voltage measurements are presented for both silicon and SiC power MOSFETs.

High-Voltage Isolated Gate Drive Circuit for 10 kV, 100 A SiC MOSFET/JBS Power Modules

A high-current, high-voltage-isolated gate drive circuit developed for characterization of high-voltage, high- frequency 10 kV, 100 A SiC MOSFET/JBS half-bridge power modules is presented and described. Gate driver characterization and simulation demonstrate that the circuit satisfies the gate drive requirements for the SiC power modules in applications such as the DARPA WBST-HPE solid state power substation (SSPS). These requirements include 30 kV voltage-isolation for the high-side MOSFETs, very low capacitance between the ground and floating driver sides, and 20 kHz operation. Block diagram and detailed discussion of principles of operation of the gate drive circuit are given, together with measured and simulated waveforms of performance evaluation.

Electro-thermal simulation of 1200 V 4H-SiC MOSFET short-circuit SOA †

The purpose of this paper is to introduce a dynamic electro-thermal simulation and analysis approach for device design and short-circuit safe-operating-area (SOA) characterization using a physics-based electro-thermal Saber®* model. Model parameter extraction, simulation, and validation results are given for several commercially available 4H-silicon carbide (SiC) power MOSFETs with a voltage rating of 1200 V and with current ratings of 31.6 A and 42 A. The electro-thermal model and simulations are used to analyze the short-circuit SOA including the measured failure time (tfailure) and simulated device internal junction temperature (Tj) at failure for different gate voltages (VGS) and drain voltages (VDS).

Comparison of 4.5 kV SiC JBS and Si PiN diodes for 4.5 kV Si IGBT anti-parallel diode applications

A new 60 A, 4.5 kV SiC JBS diode is presented, and its performance is compared to a Si PiN diode used as the antiparallel diode for 4.5 kV Si IGBTs. The I-V, C-V, reverse recovery, and reverse leakage characteristics of both diode types are measured. The devices are also characterized as the anti-parallel diode for a 4.5 kV Si IGBT using a recently developed high-voltage, double-pulse switching test system. The results indicate that SiC JBS diodes reduce IGBT turn-on switching loses by about a factor of three in practical applications. Furthermore, the peak IGBT current at turn-on is typically reduced by a factor of six, resulting in substantially lower IGBT stress. Circuit simulator models for the 4.5 kV SiC JBS and Si PiN diodes are also developed and compared with measurements.

Long-Term Stability Test System for High-Voltage, High-Frequency SiC Power Devices

This paper presents a test system developed for long-term stability characterization of 10 kV Silicon Carbide (SiC) power MOSFETs and SiC diodes under 20 kHz hard switching conditions. The system is designed to test a single power switch and a single power diode for continuous or burst switching conditions up to 5 kV and 5 A. The test system includes a 4.5 kV to 5 kV boost converter to emulate a 22.5 kW hard switching power converter. An additional DC-DC converter is used to recover the power processed by the boost converter. The design criteria, simulation, and construction of the test system are discussed in this paper and the system operation is demonstrated using various high voltage devices including 4.5 kV Silicon IGBTs, 10-kV SiC MOSFETs and 15 kV stacked silicon diodes.

Circuit simulation model for a 100 A, 10 kV half-bridge SiC MOSFET/JBS power module

This paper presents the simulation of a 100 A, 10 kV silicon carbide (SiC) half-bridge power module operating at 20 kHz in a behavioral boost converter circuit. In the half-bridge power module, 10 kV SiC power MOSFETs are used as the upper and lower switches, where 10 kV SiC junction barrier Schottky (JBS) anti-parallel diodes along with 100 V silicon JBS series reverse-blocking diodes are used to protect the SiC MOSFETs from reverse conduction. The behavioral boost converter is designed to operate a single power switch and a single power diode for continuous 20 kHz hard switching conditions at 5 kV and 100 A. The test circuit contains the model for the 100 A, 10 kV SiC half-bridge power module where the upper MOSFET gate is turned off. The simulated waveforms demonstrate fast switch performance (<100 ns) with minimal turn-on current spikes resulting from charging the capacitances of the other MOSFET and JBS diodes in the module. The results also indicate that the combination of the 10 kV SiC JBS anti-parallel diode with the series low-voltage silicon JBS reverse-blocking diode is effective in protecting the SiC MOSFETs from reverse conduction.

Automated parameter extraction software for silicon and high-voltage silicon carbide power diodes

This paper presents an automated parameter extraction software package developed for constructing silicon (Si) and silicon carbide (SiC) power diode models, which is called DIode Model Parameter extrACtion Tools (DIMPACT). This software tool extracts the data necessary to establish a library of power diode component models and provides a method for quantitatively comparing between different types of devices and establishing performance metrics for device development. To verify the accuracy of DIMPACT, the extracted model parameter sets are incorporated into the circuit simulation software to compare model predictions with measured static and transient diode characteristics. In this paper, the DIMPACT parameter extraction results are demonstrated for a 45 V, 15 A Si Schottky diode; a 600 V, 200 A Si PiN diode; a 10 kV, 5 A SiC Junction Barrier Schottky (JBS) diode; and a 10 kV, 20 A SiC PiN diode. The validation results indicate that the model parameters extracted using DIMPACT are accurate.

Physics-based electro-thermal Saber model and parameter extraction for high-voltage SiC buffer-layer IGBTs

The purpose of this paper is to present a physics-based electro-thermal Saber®* model and parameter extraction sequence for high-voltage SiC buffer layer n-channel insulated gate bipolar transistors (IGBTs). This model was developed by modifying and extending the previously developed physics-based silicon buffer layer IGBT electrothermal model and IGBT Model Parameter extrACtion Tools (IMPACT) to include SiC specific device and material properties. The validated simulation results in this paper demonstrate that the new electro-thermal Saber® model for high-voltage SiC buffer layer n-channel IGBTs can be used to describe the static and dynamic behaviors for a wide range of device designs and circuit conditions for IGBTs with blocking voltages from 12 kV to 20 kV. The new physics-based model provides both device and circuit predictive capability.

Performance of Hybrid 4.5 kV SiC JBS Freewheeling Diode and Si IGBT

The performance of Junction Barrier Schottky (JBS) diodes developed for medium voltage hard-switched Naval power conversion is reported. Nominally 60 A, 4.5kV rated JBS freewheeling diodes were paired with similarly rated Si IGBTs and evaluated for temperature dependent static and dynamic characteristics as well as HTRB and surge capability. The SiC JBS/Si IGBT pair was also directly compared to Si PiN diode/Si IGBT with similar ratings. Compared to Si, the SiC freewheeling diode produced over twenty times lower reverse recovery charge leading to approximately a factor-of-four-reduction in turn-on loss. Alternatively, for equivalent total switching loss, the SiC JBS/Si IGBT hybrid configuration allows for at least a 50% increase in specific switched power density. Reliability testing showed the devices to be robust with zero failures.