Silicon Carbide DMOSFETs Research Articles

Stress Engineering for Drive Current Enhancement in Silicon Carbide (SiC) Power MOSFETs

The poor interface quality of the Silicon Carbide/oxide (SiC/SiO2) interface severely degrades the electron surface channel mobility in SiC-based power devices. Based on transfer characteristic simulations (with a deck calibrated to experimental data), this work predicts improved mobility with stress engineering, a well-established technique for performance enhancement in low power silicon (Si) transistor technology. Process simulation of Si and SiC-based devices with Silicon Nitride (Si3N4) stressor layer has been carried out to estimate the stress generated in the channel. SiC D-MOSFET we have also computed the effect of varying stress magnitude, direction, and position in the device.

Power SiC DMOSFET Model Accounting for Nonuniform Current Distribution in JFET Region

The main goal of this paper is development of a new circuit-based silicon carbide (SiC) DMOSFET model which physically represents the mechanism of current saturation in power SiC DMOSFET. Finite-element simulations show that current saturation for a typical device geometry is due to 2-D carrier distribution effects in the JFET region caused by current spreading from the channel to the JFET region. For high drain-source voltages, most of the voltage drop occurs in the current spreading region located in the JFET region close to the channel. A new model is proposed that represents the nonuniform current distribution in the JFET region using a nonlinear voltage source and a resistance network. Advantages of the proposed model are that a single set of equations describes operation in both the linear and saturation regions, and that it provides a more physical description of MOSFET operation.

Modeling and Design of High Temperature Silicon Carbide DMOSFET Based Medium Power DC-DC Converter

Silicon Carbide (SiC) is a promising new material for high power high temperature electronics applications. SiC Schottky diodes are already finding wide acceptance in designing high efficiency power electronic systems. We present TCAD and Verilog-A based modeling of SiC DMOSFET, and the design and analysis of a medium power DC-DC converter designed using SiC power DMOSFETs and SiC Schottky diodes. The system is designed as a 300W boost converter with a 12V input and 24V/36V outputs. The SiC power converter is compared to another designed with commercially available Silicon power devices to evaluate power dissipation in the DMOSFETs, transient response of the system and its conversion efficiency. SiC DMOSFETs are characterized at high temperature by developing temperature dependent TCAD and Verilog-A models for the device. Detailed TCAD modeling allows probing inside the device for understanding the physical processes of transport, whereas Verilog-A modeling allows us to define the complex relationship of interface traps and surface physics that is typical to SiC DMOSFETs in a compact analytical format that is suitable for inclusion in commercially available circuit simulators.

High Temperature (250 °C) Silicon Carbide Power Modules With Integrated Gate Drive Boards

Arkansas Power Electronics International, Inc., in collaboration with the University of Arkansas and Rohm, Ltd., have developed a high-temperature, high-performance Silicon-Carbide (SiC) based power module with integrated gate driver. This paper presents a description of the single phase half-bridge module containing eight Rohm 30 A SiC DMOSFETs in parallel per switch position. The electrical and thermal performance of the system under power is also presented.