Silicon carbide substrates are becoming the most popular material for processing gallium nitride. Out of many possible SiC crystalline structures there are two most popular are 4H and 6H, but their material properties aren't much different.
Some of this info came from Russia's Ioffe Institute. Note that SiC crystals are anisotropic; if you intend to design CPW circuits on SiC the dielectric constant is somewhat higher than the value of 9.66 given below.
| Formula or Composition: |
SiC |
| Dielectric Constant (εR): |
9.66 |
| Dissipation Factor (a.k.a. loss tangent, or tanδ): |
0.003 |
| Temperature Coefficient of εR: |
ppm/°C |
| Bulk Resistivity: |
1E5 Ohm-cm |
| Temperature Coefficient of Resistivity (TCR): |
ppm/°C |
| Mass Density: |
3.2 gr/cc |
| Specific Heat: |
0.69 J/g/°C |
| Thermal Conductivity (k): |
350 W/m°C |
| Temperature Coefficient of Expansion (TCE): |
4.8 ppm/°C |
| Melting Point |
2700 °C
4892 °F
|