THIN-FILM FERRITES FOR MICROWAVE AND MILLIMETER-WAVE APPLICATIONS

The growth and properties of ferrite films prepared by three techniques for applications in microwave and millimeter-wave devices are reviewed. Yttrium-iron garnet films, grown by liquid phase epitaxy with thickness > 100 μm and ΔH < 1 Oe, are required for efficient operation of devices such as microwave filters and limiters. Nickel-zinc ferrite films for the fabrication of circulators at high microwave frequencies have been deposited by spin-spray plating onto GaAs substrates at temperatures up to 100°C. Devices using these films can be monolithically integrated with GaAs circuits. Oriented barium-ferrite films for application at millimeter-wavelengths have been deposited by sputtering. © 1990.