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Hard substrates include ceramics such as alumina, aluminum nitride and beryllium oxide, and are desirable for applications where bare die (chips) are used such as in a hybrid module. Ceramics are used because they can withstand the extreme heat used in wirebonding.
Semiconductor substrates such as GaAs, InP and silicon are used in manufacturing RFICs.
Some of these numbers came from Aeroflex, TriQuint, CREE.
| Material |
Symbolorformula |
Dielectric constant |
Dissipation factor (tan ) |
Coefficient of thermal expansion ppm/°C |
Thermal conductivity (W/m°C) |
Mass density(gr/cc) |
| Alumina 99.5 % |
Al2O3 |
9.8 |
0.0001 |
8.2 |
35 |
3.97 |
| Alumina 96% |
Al2O3 |
9.0 |
0.0002 |
8.2 |
24 |
3.8 |
| Aluminum Nitride |
AlN |
8.9 |
0.0005 |
7.6 |
290 |
3.26 |
| Beryllium Oxide |
BeO |
6.7 |
0.003 |
6.05 |
250 |
|
| Gallium Arsenide |
GaAs |
12.88 |
0.0004 |
6.86 |
46 |
5.32 |
| Gallium Nitride |
GaN |
|
|
|
|
6.1 |
| Indium Phosphide |
InP |
12.4 |
|
|
|
|
| Porcelain |
|
6.5 |
|
|
|
|
| Quartz |
|
3.8 |
0.0001 |
0.6 |
5 |
|
| Sapphire (note1) |
|
9.3, 11.5
|
|
|
|
|
| Silicon (high resistivity) |
Si (HRS) |
|
|
2.5 |
138 |
2.33 |
| Silicon (low resistivity) |
Si (LRS) |
|
|
|
|
|
| Silicon Carbide |
SiC |
10.8 |
0.002 |
4.8 |
350 |
3.2 |
Note 1. Anisotropic dielectric material, Er=9.3 perpendicular to C-axis, 11.5 parallel to C-axis.