18.104.22.168.2 GaAs and MMIC
Gallium arsenide (GaAs) devices are now being used in military
and commercial systems. GaAs offers some significant advantages over silicon
that can result in improved device performance. It has unique qualities which
allow the fabrication of devices that can operate at frequencies which
outperform their silicon counterparts. In addition, GaAs offers inherent
radiation hardness and improved power efficiency for high frequency digital
and analog circuitry.
Monolithic Microwave Integrated Circuits (MMIC) are replacing
hybrid microwave devices throughout the industry as a result of the Defense
Advanced Research Project Agency (DARPA) sponsored Monolithic Microwave
Millimeter Wave Integrated Circuit (MIMIC) program. Before the development of
GaAs MMIC technology, discrete packaged devices and multifunction assemblies
were commonly utilized in microwave applications. MMIC technology, however,
offers several advantages including weight/size reduction, process tolerance
and uniform performance with a reduced need of tuning circuits. These
advantages, combined with GaAs’s inherent performance advantages, have led to
significant interest in the technology.
To date, information concerning the reliability of GaAs and MMIC
components has shown varying results and inconsistent activation energies for
a specific failure mechanism. Thus, the absolute reliability of GaAs devices
is not easy to predict with accuracy, though an approximation can be made
based on government/industry reliability studies.