Vishay EFI offers a variety of substrates for custom thin film solutions. The three substrates mainly used in our custom solutions are Alumina (Al2O3), Aluminum Nitride (AlN) and Beryllium Oxide (BeO) either lapped, as-fired or polished surface finishes. Alumina is a cost-effective solution that is commonly used for its surface quality and high frequency performance.
For power applications and when high thermal conductivity is needed, AlN and BeO substrates are optimal. Important factors to consider when choosing a substrate include dielectric constant, surface finish, loss tangent, thermal conductivity, coefficient of thermal expansion and cost. Vishay EFI produces on substrates that range in thickness from 5 mils to 60 mils and range in size from 20 x 20 mils to 4.50 in x 4.50 in.
Ceramic Material Selection Material Surface Finish [u"] Thermal Conductivity @ 25°C [W/mK] CTE [ppm/°C] Uses Benefits Alumina
< 12 lap
< 4 asf
35 8.4 Standard hybrid or medium power microwave Best cost effective choice AIN
10 - 20 lap
< 2 pol
4.6 High power microwave Ideal CTE match to silicon devices, high termal conductivity BeO
15 - 40 lap
< 3 pol
265 9.0 High power DC/RF/Microwave High Thermal Conductivity Silicon Polished 157 3.9 DC circuit-medium/high power Best choice for high density fine line interconnections Quartz 60/40 Optical Finish 1.4 - 1.5 0.5 - 0.65 Microwave-Millimeter-wave, low power / low shunt capacitance High density patterns, high voltage, low loss tangent / low CTE Titanates Per Customer Requirement RF/Microwave with high Q Dielectric properties Ferrites Per Customer Requirement Circulators / Isolators Magnetic sensitivity Sapphire Per Customer Requirement Millimeter-wave / optical circuits with special electrical or mechanical requirements Low loss tangent, optical surface finish