EV traction inverters
800 V SiC modules where fast charging and high power density push the ceramic-copper joint to its limit.
As SiC devices push power density and junction temperature higher, the substrate — not the chip — is often the weak link. Si₃N₄ AMB substrates survive the thermal cycling that cracks alumina and AlN, which is why they are now mainstream in 800 V SiC traction inverters.
A traction inverter sees thousands of thermal cycles per year, each one flexing the ceramic-copper joint. Alumina is cheap but cracks; AlN conducts heat best but is brittle and shocks easily. Silicon nitride trades a little peak conductivity for far higher strength and the lowest thermal expansion mismatch with the SiC chip — so the joint survives, and the module keeps its rated life.
Three common ceramics, three different failure modes. Pick by what actually kills your module.
| Property | Al₂O₃ (Alumina) | AlN | Si₃N₄ |
|---|---|---|---|
| Bending strength (MPa) | ~300 | ~300 | ≥ 600 |
| Thermal conductivity (W/m·K) | ~24 | ~170 | ≥ 80 |
| Thermal expansion (×10⁻⁶/K) | ~7.2 | ~4.5 | ~3.0 |
| Thermal-cycle reliability | Fair | Good | Excellent |
| Best for | Cost-sensitive | Max heat removal | Harsh cycling |
When AlN wins: if your bottleneck is pure heat flux — a high-current industrial converter with stable mounting and few cycles — AlN's ~170 W/m·K still conducts better. Choose Si₃N₄ when mechanical shock, vibration and thermal cycling dominate, which is the case in every vehicle.
| Item | Standard capability |
|---|---|
| Material | Gas-pressure sintered Si₃N₄, ≥ 3.20 g/cm³, made on dedicated substrate lines with controlled thickness and flatness. |
| Flexural strength | ≥ 600 MPa — the property that sets thermal-cycle life. |
| Thermal conductivity | ≥ 80 W/m·K at room temperature. |
| Thermal expansion | ~3.0 ×10⁻⁶/K (RT–1000 °C), close to SiC. |
| Substrate size | Up to ~140 × 190 mm (larger footprints quoted per drawing). |
| Surface | Fine-ground, thickness- and flatness-controlled for AMB brazing; surface state agreed per project. |
| Inspection | Density, phase (XRD), microstructure (SEM) and strength testing in-house; reliability (Weibull) lab on site. |
Both sides of the substrate are supplied ready for the customer's own AMB / DBC brazing process, or we can quote the finished brazed substrate with your pattern.
800 V SiC modules where fast charging and high power density push the ceramic-copper joint to its limit.
String and central inverters that cycle daily with the sun, plus storage converters with steep load swings.
Long-life power stacks where a substrate failure means pulling a converter out of service.
Also supplied for SiC module baseplates and other power-electronics assemblies where mechanical strength and cycling life matter more than the last few W/m·K.
NDA signed on request before drawings change hands.
NitriCeram is a brand of Shandong Dolphin Technology Co., Ltd., operating an integrated line from powder synthesis through forming, gas-pressure sintering, HIP, precision machining and in-house testing. The AMB Si₃N₄ substrate line was launched in 2023 for EV power modules, and today runs as two dedicated production lines.
We reply within 24–48 hours with a manufacturability review, recommended grade and price. NDA signed on request before drawings change hands.
Reading first? See the technical article Si₃N₄ vs AlN vs Al₂O₃: Choosing a Power-Module Substrate.
