Gallium nitride past, present, and future

Gallium nitride (GaN) has been known for some time. The first US Government research funding began in 1970 with substantial increases in 1982 and again in 1993 and 1995. While the biggest initial commercial interest is in visible light emission, there will be substantial commercial and governmental use of ultra violet (UV) applications as well. It is, however, in the microwave and the millimeter wave spectrum where GaN will engender new systems enabling applications. It is here where anticipated fully digital signal synthesis and beam steering technology will require broadband, linear, efficient amplifiers with moderate power levels; GaN currently appears to be the most promising candidate semiconductor for such amplifiers.