Ge Nanocrystals Embedded in a SiO2 Matrix Obtained from SiGeO Films deposited by LPCVD Articles uri icon

authors

  • RODRIGUEZ, A
  • RODRIGUEZ, T
  • SANGRADOR MARTINEZ, FRANCISCO JAVIER
  • MORANA, B.
  • KLING, A
  • BALLESTEROS PEREZ, CARMEN INES

publication date

  • April 2010

start page

  • 45032

issue

  • 4

volume

  • 25

International Standard Serial Number (ISSN)

  • 0268-1242

Electronic International Standard Serial Number (EISSN)

  • 1361-6641

abstract

  • SiGeO films were deposited by LPCVD using Si2H6, GeH4 and O2 as reactive gases and furnace annealed to segregate the excess of Ge in the form of nanocrystals embedded in a SiO2 matrix in a low temp. budget process
    fully compatible with current processing technologies. For low GeH4
    partial pressures (4.8 mTorr) and a deposition temp. of 450 C, the
    deposited film consists of a SiO2 matrix incorporating Ge atoms, and no
    Ge oxides are detected. After annealing of the sample at a temp. of 600
    C, quasi-spherical isolated Ge nanocrystals homogeneously distributed
    throughout the whole film thickness, with diams. ranging from 4.5 to 9
    nm and an areal d. of around 7 1011 cm-2, are formed while the SiO2
    matrix holds its original compn. Increasing the GeH4 partial pressure
    results in only a slight increase in the d. of nanoparticles with no
    significant changes in their diams. and a matrix is formed by a mixt. of
    Si and Ge oxides. A decrease in the deposition temp. results in very
    slow growth rates. Finally, increasing the annealing temp. causes no
    improvement in the sample characteristics, but a transformation of the
    matrix into a mixt. of Si and Ge oxides takes place and Ge diffusion
    processes start to appear. on SciFinder(R).