MOCVD zinc oxide films for wide bandgap applications

ZnO is a wide bandgap (3.2 eV) semiconductor with potential application in LEDs, lasers, and transparent transistors, among other uses. These applications require uniform thickness, high quality materials (amorphous, poly- or single crystal), pinhole- and defect-free-single-and multilayer-conformal coatings. These attributes are generally best achievable by MOCVD. We have mounted a significant effort to develop automated MOCVD systems and process technologies for single and multicomponent oxides. The reactors use high speed rotation and are of a vertical orientation built to all metal UHV standards. We have demonstrated reactor scaled performance from 3" to 12" diameter depositions planes with modeling scales through 24" diameter. Metalorganics are used for zinc and dopant sources as well as dopant gases to optimize performance at low pressures. In this paper we will discuss our most recent results with epitaxial ZnO films, achievements in p-type doping, multilayer structures, and polycrystalline doped ZnO films.