A NEW APPROACH FOR SYNTHESIZING GE QUANTUM CRYSTALLITES EMBEDDED IN ASIN(X) FILMS

In this letter, we present a new approach for synthesizing Ge quantum crystallites embedded in a-SiN(x) films. On the basis of preferential chemical bonding formation of Si-N and Ge-Ge, thin films with Ge clust ers embedded in a-SiN(x) matrix have been prepared by the plasma enhan ced chemical vapor deposition method with reactant gases of SiH4, GeH4 and NH3 mixed in hydrogen plasma at substrate temperature of 250-degr ees-C. Then the as-deposited films were annealed at 800-degrees-C for 30 min in the vacuum for the crystallization of Ge clusters and the gr owth of nanometer-sized Ge quantum crystallites. These samples were ch aracterized by infrared absorption spectra, transmission electron micr oscopy, x-ray diffraction, and Raman scattering spectra. The average s ize of Ge crystallites was found to be about 200 angstrom. By choosing conditions of the deposition and thermal-annealing treatment, the siz e of Ge quantum crystallites can be prepared in a controlled manner.