Micro and millimeter waves by virtue of their frequency range being in the electromagnetic spectrum, have their special needs addressed by GaAs / GaN / SiGe chips.
GaAs is a well used and well known compound semiconductor, it has been used in a multitude of applications and serves as a benchmark against which the performance of other compound semiconductors are measured. Current research in GaAs include: non-stoichiometric GaAs (or LT-GaAs), increasing the density of GaAs integrated Circuits, and GaAs on Silicon.
Silicon germanium (SiGe) is a semiconductor technology made for wireless applications. It offers the high-speed, high-frequency performance needed for wireless systems, and it provides the potential for integrating analog, RF, and digital functions on a single integrated circuit based on low-cost Si wafers.
