Semiconductor & Electronics · AlN Substrates

AlN ceramic substrates for
power & RF packaging.

Aluminum nitride substrates for power module packaging, RF device packaging, and high-frequency electronics. Thermal conductivity 170 W/m·K — 8× Al₂O₃ — CTE 4.5 ppm/°C closely matched to SiC and GaN-on-SiC. The substrate material for next-generation EV power modules.

170 W/m·K

Thermal Conductivity

4.5 ppm/°C

CTE — matches SiC/GaN

15 kV/mm

Dielectric Strength

DBC/AMB

Metallisation Ready

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★ Why AlN enables higher power density

AlN substrate thermal resistance vs alternatives

8×

AlN conductivity vs Al₂O₃

4.5 ppm/°C

CTE vs SiC 4.0 ppm/°C

1.8 kW/cm²

Modern SiC module power density

1 kW/cm²

Max density with Al₂O₃ substrate

Certifications & Standards

ISO 9001IATF 16949CERoHS · REACHUL Recognized

1.8 kW/cm²

Power density of modern SiC power modules — AlN substrate thermal resistance is the limiting factor

8×

AlN thermal conductivity vs Al₂O₃ — decisive for high-power-density packaging

4.5 ppm/°C

AlN CTE — closest match to SiC (4.0) and GaN-on-SiC (4.2) of any ceramic substrate

Electric vehicle power modules — the fastest-growing AlN substrate application

01 · The Application

AlN substrates enable higher power density.

📐

AlN substrate — DBC metallised for SiC power module

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Power module substrates must simultaneously provide: electrical isolation (dielectric strength ≥15 kV/mm), maximum thermal conductivity to minimise junction temperature rise, and CTE matched to the die to prevent solder fatigue. AlN achieves all three — making it the substrate of choice for SiC and GaN power modules.

AlN CTE of 4.5 ppm/°C is the closest match to SiC (4.0 ppm/°C) and GaN-on-SiC (4.2 ppm/°C) of any ceramic substrate — virtually eliminating CTE-mismatch solder fatigue in SiC and GaN power modules.

Technical Requirements

Thermal conductivity170 W/m·K

CTE4.5 ppm/°C — matches SiC/GaN

Dielectric strength≥15 kV/mm

Surface finishRa ≤0.4µm — metallisation ready

02 · Material Selection

AlN vs Al₂O₃ for

power module substrates

★ Recommended

Aluminum Nitride (AlN)

170 W/m·K · CTE 4.5 · next-gen SiC/GaN substrate

✓
170 W/m·K thermal conductivity — 7× lower thermal resistance than Al₂O₃
✓
CTE 4.5 ppm/°C — virtually eliminates CTE mismatch solder fatigue with SiC/GaN
✓
Ra ≤0.4µm — ready for DBC and AMB metallisation
✓
Dielectric strength ≥15 kV/mm — qualified for 1,200V SiC module isolation
✓
AEC-Q200 grade material documentation for automotive qualification

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Also Available

Alumina (Al₂O₃)

25 W/m·K · CTE 7.4 · legacy substrate

→
Lower cost — standard ceramic substrate for <600W modules
→
Established supply chain and processing
⚠
CTE mismatch 7.4 vs SiC 4.0 — causes solder fatigue in high-cycle power modules
⚠
7× higher thermal resistance — limits power density to ~300 W/cm²

Power electronics substrate applications

Enabling next-generation
SiC and GaN power modules.

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AlN substrate program

CTE 4.5 ppm/°C: closest match to SiC/GaN of any ceramic
DBC/AMB ready: Ra ≤0.4µm, semiconductor-grade clean
Panel sizes: 50×50mm to 150×200mm standard
AEC-Q200: automotive power electronics documentation
EV qualified: supply to Tier-1 EV drivetrain suppliers

03 · Power Module Substrate Failures

Critical substrate failure modes in power cycling.

Two failure modes dominate — both are more severe with Al₂O₃ substrates than with AlN.

CTE mismatch solder fatigue

When substrate CTE differs from die CTE (Al₂O₃ 7.4 vs SiC 4.0 ppm/°C), differential expansion during power cycling accumulates as solder joint fatigue. AlN's 4.5 ppm/°C virtually eliminates this with SiC and GaN dies.

AlN fix → CTE 4.5 ppm/°C — same order of magnitude as SiC/GaN. Solder fatigue life 5–10× longer than Al₂O₃ in SiC module power cycling.

Thermal resistance bottleneck

Al₂O₃ at 25 W/m·K creates 0.3°C·cm²/W substrate thermal resistance — limiting power density to ~300 W/cm². AlN at 170 W/m·K reduces this 7× to ~0.04°C·cm²/W, enabling >1 kW/cm².

AlN fix → 7× lower thermal resistance enables the junction temperature margin required for reliable SiC module operation at 1.8 kW/cm².

Metallisation delamination

Poor AlN surface finish or contamination prevents DBC copper adhesion. Our substrates are supplied Ra ≤0.4µm and semiconductor-grade clean — validated to 1,000 thermal cycles −55°C to +150°C.

AlN fix → Ra ≤0.4µm surface finish standard. 1,000-cycle delamination test data available for qualification.

04 · Engineering FAQ

Questions from power module engineers.

What CTE does AlN match?

AlN CTE 4.5 ppm/°C. SiC: 4.0. GaN-on-SiC: 4.2. The closest CTE match of any ceramic substrate to next-generation power semiconductors. Al₂O₃ at 7.4 is significantly mismatched.

DBC and AMB compatible?

Yes — Ra ≤0.4µm surface finish standard. Both DBC and AMB metallisation processes validated. Bare substrates or referral to metallisation partners.

Standard sizes?

50×50mm, 100×100mm, 120×180mm, 150×200mm standard panels. Custom sizes and diced substrates to module footprint with 4-week lead time.

AEC-Q200 certification for automotive?

AEC-Q200 grade AlN with full lot traceability, PPAP documentation, and endurance test data for automotive power electronics qualification.

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