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Hard Substrate Materials

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Find more information on co-fired ceramics here.

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.

Author : Unknown Editor

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