화학공학소재연구정보센터
Materials Science Forum, Vol.457-460, 1553-1556, 2004
Plasma-assisted molecular beam epitaxial growth of AlN films on vicinal sapphire (0001) substrates
Epitaxial growth of AlN films on vicinal (0001) sapphire substrates by rf-MBE is investigated. RHEED, HRXRD, CL and AFM are used to characterize the qualities of AlN films. it is found that AlN growth is two-dimensional (2D) by the RHEED observations. HRXRD and CL measurements illustrate excellent structural and optical properties of AlN films. Furthermore, it is found that surface morphologies of AlN films, from 2D nucleation to step-surface features, depends on the vicinal angles of the sapphire substrates. By selecting a proper vicinal angle (0.5degrees), ultra-flat AlN surface with clear straight mono-atomic-layer steps is realized with the rms being as small as 0.2 nm within a 2x2 mum scanning. The usage of vicinal sapphire substrates clearly demonstrates a merit to achieve ultra-flat surface of III-nitride films.