Doping effects on the kinetics of solid-phase epitaxial growth of amorphous alumina thin films on sapphire Academic Article uri icon

abstract

  • The effects of doping on the kinetics of solid-phase epitaxial growth of amorphous alumina have been studied. Amorphous alumina Al2O3) thin films, 200265 mm thick, were deposited on to (0001) sapphire substrates by electron-beam evaporation. Iron or chromium atoms were uniformly doped into the films during deposition to cation concentrations below 5 cationic %. The kinetics of the epitaxial growth were studied at 8001050C in flowing oxygen gas by insitu time-resolved reflectivity techniques as well as by ion backscattering and channeling techniques. A phase transformation sequence from amorphous through gamma to alpha alumina has been observed in all the undoped and doped films. The transformation from to alumina is a thermally activated process with an activation energy of 5.00.2 eV, independent of the presence of dopants. However, the presence of dopants affects the overall transformation rate. Fe enhances while Cr slows the growth rate relative to the undoped case.

published proceedings

  • Applied Physics Letters

author list (cited authors)

  • Yu, N., Simpson, T. W., McIntyre, P. C., Nastasi, M., & Mitchell, I. V.