Growth of boron nitride thin films on silicon substrates using new organoboron precursors

Thin films of BN have been deposited on silicon substrates in the temperatu re range of 600 to 900 degrees C by supersonic molecular jet epitaxy and pl asma-assisted MOCVD using new organoboron precursors such as borane-triethy lamine complex (BTEA) and tris(sec-butyl)borane (TSBB). Hydrogen was used a s carrier gas, and additional nitrogen and ammonia as reactive gases were s upplied by either through nozzle or via remoted plasma. Crack-free, polycry stalline hexagonal BN films with nano-size crystals were successfully grown at temperature as low as 750 degrees C using BTEA. With increasing substra te temperatures to 900 degrees C, however, the h-BN films changed polycryst alline with smoother surface and larger crystals. The changes of relative f ilm quality with deposition temperature and reactive gas have been confirme d with FTIR. Nitrogen plasma enhanced the film quality and the stoichiometr y, and removed the surface carbon effectively rather than ammonia and hydro gen plasmas molecular beam. Wide band gaps were calculated using optical tr ansmittance measurements.