(Invited) Characteristics of a Wire-Bonding-Less SiC Power Module Operating in a Wide Temperature Range

Introduction

Using high-speed switching, wide bandgap semiconductor devices can reduce on-resistance in the on-state to realize low power converter losses. In addition, SiC power devices can be operated in high temperatures; thus, their cooling systems can be reduced in size or removed all together, thereby increasing the power density of the power converter. In this study, we designed and fabricated a SiC power module with a built-in snubber circuit. This power module is operable in high temperatures over 200 degrees C.

Design of Power Module for High-Temperature Operation

The manufactured power module, its components, and its circuit diagram are shown in Fig. 1. The module size is 30 × 44 × 29 mm³. Active metal brazing copper (AMC) substrates sandwich the four SiC-metal–oxide–semiconductor field-effect transistors (MOSFETs) in this structure. Two AMC substrates connect via the metal block. The C–R  snubber circuit is built-in on the surface of AMC1 (Fig. 1(b)). The SiC-MOSFET and AMC1 are joined by a flip-chip-bonding technique using an Al bump. The others are joined by Au–Ge solder. Fig. 2 shows the 50-kHz switching waveforms. Fig. 3 shows the circuit configuration for the Fig. 2 waveforms. This power module can realize high-speed switching in a fall time tf @ 25 ns. Surge voltage and ringing are suppressed by the built-in snubber circuit.

Acknowledgment

This work was supported by Council for Science, Technology and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), "Next-generation power electronics/Consistent R&D of next-generation SiC power electronics", and "the Novel Semiconductor Power Electronics Project Realizing Low Carbon Emission Society" (funding agency: NEDO).