diamondSingle-crystal SiC

Silicon Carbide (SiC) Submounts

Single-crystal SiC submounts for lidar emitters, GaN RF power modules, and high-power laser bars. 350–400 W/m·K — the highest thermal conductivity of any practical ceramic substrate. FerraLink is one of the only qualified sources accessible to US engineering teams.

scienceOrder SiC samples — from $50Request custom quote
SEM micrograph of single-crystal SiC submount at 2000× magnification
thermostat

Thermal conductivity

350–400 W/m·K

Single-crystal — no grain boundaries

diamond

Crystal structure

Single crystal

Phonon transport without grain scattering

schedule

Lead time

2–4 weeks

10-piece sample box — $500

Why single-crystal SiC delivers the highest thermal performance

Thermal conductivity in ceramic submounts is governed by phonon transport. In polycrystalline materials like ALN, phonons scatter at grain boundaries — each boundary acts as a thermal resistance that limits bulk conductivity to 170–210 W/m·K.

FerraLink SiC submounts use single-crystal silicon carbide. Without a polycrystalline grain structure, phonons travel through the lattice with minimal scattering. The result is 350–400 W/m·K — roughly twice ALN and 13–15× standard alumina. This is visible in SEM: single-crystal SiC shows smooth crystalline facets, while polycrystalline ALN shows distinct grains and grain boundaries at the same magnification.

For pulsed lidar emitters, multi-watt laser bars, and GaN power devices where junction temperature spikes must be absorbed in microseconds, that difference in transient thermal spreading is often the deciding factor in module reliability.

Material characterization

SiC (single crystal)

SEM micrograph of single-crystal silicon carbide submount at 2000× magnification — smooth crystalline facets without grain boundaries
Single-crystal SiC, 2000×. Smooth crystalline facets — no polycrystalline grain structure.
EDS spectrum of SiC submount showing silicon and carbon peaks
EDS composition verification — Si and C peaks confirm stoichiometric silicon carbide.

FerraLink SiC submounts use single-crystal silicon carbide. Without grain-boundary phonon scattering, thermal conductivity reaches 350–400 W/m·K — the highest of any practical ceramic substrate available to packaging engineers.

SiC vs. other submount materials

MaterialStructureThermal conductivityCTE (ppm/°C)Best application
SiC (FerraLink)Single crystal350–400 W/m·K3.7–4.3Lidar, laser bars, GaN RF, EV power
ALN (FerraLink)Polycrystalline170–210 W/m·K4.3–4.6InP/GaAs laser diodes, telecom
Alumina (Al₂O₃)Polycrystalline26–30 W/m·K6.5–7.5Low-power, cost-sensitive
Silicon (Si)Single crystal150 W/m·K2.6VCSEL arrays, low-power photonics

Applications

radar

Automotive & Industrial LiDAR

Pulsed 905 nm and 1064 nm emitters. Single-crystal SiC handles peak-power thermal spikes that polycrystalline ALN cannot match.

bolt

High-Power Laser Bars

Multi-watt CW and quasi-CW bars where power density exceeds 100 W/cm². SiC is the default when ALN thermal margin is insufficient.

cell_tower

GaN RF Power

GaN HEMT and MMIC modules. SiC CTE (3.7–4.3 ppm/°C) pairs well with GaN devices and high-current metallization.

electric_car

Power Electronics

EV inverters, industrial motor drives, and high-voltage modules where substrate thermal resistance directly limits power density.

Metallization options

Ti / Pt / AuMost common

Universal — wire bonding, flip-chip, die attach. Pt barrier prevents Ti diffusion.

Ti / Ni / Au

Higher Au thickness for solder die attach. Robust against reflow profiles up to 300°C.

Au/Sn 80/20 (3–5 µm)Recommended

Predeposited on bonding pad. Eliminates solder preform handling for laser bar attach.

Standard part numbers

Part numberSize (mm)Thickness (mm)MetallizationSample price
FL-SiC-0050.5 × 0.50.10–0.30Ti/Pt/Au$50
FL-SiC-0101.0 × 1.00.15–0.50Ti/Pt/Au or Au/Sn$50
FL-SiC-0151.5 × 1.50.20–0.50Ti/Pt/Au or Ti/Ni/Au$50
FL-SiC-0202.0 × 2.00.25–1.00Ti/Pt/Au or Au/Sn$50
FL-SiC-035455-0013.5 × 4.550.30Ti/Pt/Au + Au/Sn$50

10-piece SiC sample box — $500. Custom sizes and metallization stacks available. Send design files in DXF, DWG, or Gerber to info@ferralink.com.

Related technical guides

SiC Submounts for US Engineers: Supply & Qualification

Why single-crystal SiC is scarce and how to qualify a US-accessible source.

ALN vs SiC Submounts: Which Should You Choose?

Single-crystal vs polycrystalline microstructure and thermal performance comparison.

Hermetic Packaging for LiDAR Applications

Package types, thermal paths, and SiC submount selection for lidar emitters.

FMCW vs. Pulsed LiDAR Packaging

Why pulsed lidar at 905 nm typically requires SiC for transient thermal spreading.

Frequently asked questions

Where can I buy SiC submounts in the USA?expand_more
FerraLink supplies single-crystal SiC submounts directly to US engineering teams at www.ferralink.com/sic-submount. Standard lead time is 2–4 weeks. Samples from $50/piece or $500 for a 10-piece evaluation box.
Why is single-crystal SiC better than polycrystalline ALN for thermal conductivity?expand_more
Single-crystal SiC has no grain boundaries, so phonons scatter less and thermal conductivity reaches 350–400 W/m·K. Polycrystalline ALN shows grain boundaries in SEM and typically delivers 170–210 W/m·K.
What applications require SiC submounts instead of ALN?expand_more
Pulsed lidar emitters at 905 nm, multi-watt laser bars above ~100 W/cm², GaN RF power modules, and any application where transient thermal spreading during peak power pulses exceeds ALN capability.
What is the standard SiC submount lead time from FerraLink?expand_more
2–4 weeks for standard catalog part numbers and sample boxes. Custom sizes and metallizations typically require a 2,000 pc MOQ — send design files to info@ferralink.com for quote and lead time after DFM review.
What is the MOQ for custom SiC submounts?expand_more
Custom geometries and metallization stacks typically require 2,000 pieces. For small-volume evaluation, use standard sample boxes ($500, 10 pieces) or individual catalog samples ($50/piece) — see ferralink.com/how-we-work.

Ready to evaluate single-crystal SiC?

10-piece sample box — $500. Individual samples — $50/piece. Ships in 2–4 weeks with material certs, SEM/EDS data, and lot documentation.

Order SiC samples →DFM review