The Historic Roots of Compound Semiconductors
Source/Type: Reference Materials

April 4, 2001... The strategic importance of compound semiconductor devices is a contributing factor as to why... until relatively recently in the course of history... the compounds have remained relatively obscure, especially compared to their silicon cousins. They certainly aren't new. The most mature of the compounds, Gallium Arsenide (GaAs), has been researched and applied to leading edge device creation for over 30 years. Even some of the seemingly newest compounds, such as the Group III Nitrides (Gallium Nitride or GaN) have been worked on in laboratories worldwide for over 20 years. For many of those 20-30 years the compounds have simply been regarded as too costly to effectively develop for commercial use, thus relegated to laboratory curiosity or used only for exotic applications. 10 to 15 years ago, that all began to change.

Compound semiconductors have been in space in a variety of applications since space exploration began, primarily because they can survive the extreme cold of outer space, are more resilient to the very energetic radiation in space, and are especially efficient at cost-effectively converting sunlight to electrical energy . Night vision or 'intensifier' devices are another important dual use application. Thanks to compound semiconductor devices, a soldier in the field or sailor at sea can literally see almost as clearly as in daylight. These military systems are now finding their way to civilian applications to aid firefighters, police, and other people who must function effectively in limited light situations. Where objects emit more heat than their environment, they can now be seen using heat or Infrared (IR) detectors made from cadmium, mercury, and tellurium, known as "mercad." The US government, and many other governments around the world, continue to heavily finance development of compound semiconductor technology. Whether it be for defense applications, environmental motivation, or commercial practicality, compound semiconductor devices solve problems and provide opportunities silicon devices simply cannot address. Many photonic type devices, such as conventional and the newer high brightness (HB) LEDs and many types of lasers are totally dependent on compound semiconductor materials for their manufacture as silicon's light-emitting properties simply don't extend into those illuminating realms according to the basic laws of physics. And when it comes to lasers, all those solid state laser diodes you hear about powering everything from weapons to medical applications to the pump lasers used in next generation fiberoptic communication or "all optical" systems... those are compound semiconductors. Welcome to the world that takes us all, beyond the capability of silicon and into the future.

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