Since the early 1970s, scientists have been promoting gallium arsenide as a faster, more efficient substrate material than silicon for making integrated-circuit chips. However, the vast majority of chips are still made from silicon, which is abundant and cheap.
The most important advantage of gallium arsenide is speed. Electrons travel about five times faster in gallium arsenide than they do in silicon. Gallium arsenide also has a high resistance to electrical current before it is doped with any impurities to form circuit elements. Consequently, a gallium arsenide wafer, or substrate, is semi-insulating, whereas a silicon wafer is semi-conducting. Gallium arsenide also offers a wider range of operating temperatures than silicon and much higher radiation hardness, which is a decisive advantage for military and space programs. Another major advantage is that gallium arsenide can be doped in such way that it emits light, which makes it useful for lasers and light-emitting ...
