Metalorganic vapour-phase epitaxy

By 1968, three separate technological streams—organometallic chemistry, vacuum deposition, and compound semiconductor theory—had matured independently for decades. Harold Manasevit at North American Rockwell's Autonetics Division in Anaheim recognized they could be woven together. Working with a reactor originally designed for silicon-on-sapphire growth, he introduced trimethylgallium—a pyrophoric organometallic compound discovered in 1933 but rarely used—alongside arsine gas. The result was single-crystal gallium arsenide deposited on sapphire substrates at moderate pressures, fundamentally different from existing vacuum-based molecular beam epitaxy.

Manasevit coined the term "MOCVD" deliberately: he saw the process as broadly applicable to many materials. Chemical vapor deposition had existed since the 1960s for silicon processing. Liquid-phase epitaxy and vapor-phase epitaxy had shown that growing crystalline layers atom-by-atom was possible, but both were slow and difficult to scale. Organometallic precursors offered precise control and could be vaporized at manageable temperatures. The invention emerged convergently: Russell Dupuis at Rockwell in 1977 demonstrated the first continuous-wave room-temperature laser diode grown by MOCVD, while in Japan, Isamu Akasaki at Nagoya University built custom MOCVD reactors for gallium nitride growth. Shuji Nakamura at Nichia Chemical modified his system into the "Two-Flow MOCVD" design that by 1993 produced blue LEDs 1,000 times brighter than previous attempts.

MOCVD unlocked quantum well structures—ultra-thin layers where electrons are confined in two dimensions, essential for efficient light emission. Aixtron, founded in 1983 as a spin-out from RWTH Aachen, commercialized multi-wafer planetary reactors. Veeco entered through acquisitions and by 2012 dominated LED production. The technology remains the only viable mass-production technique for compound semiconductors, its path-dependence locked in by decades of equipment refinement.