Formation of germanium nanocrystals and amorphous nanoclusters in GeSiOx films using electron beam annealing

Electron beam annealing was used for the first time to form amorphous and crystalline germanium clusters in GeO[SiO] and GeO[SiO2] films deposited on fused silica and c-Si (100) substrates. Structural transformations of the films were investigated using Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, and high-resolution transmission electron microscopy (HRTEM). The Raman spectra show that amorphous germanium nanoclusters are present in the as-deposited GeO[SiO] film and are not observed in the as-deposited GeO[SiO2] film. The electron beam annealing parameters necessary for the formation of both amorphous and crystalline germanium nanoclusters in GeO[SiO] and GeO[SiO2] films were found. The proportion of the crystalline germanium phase is lower in GeO[SiO] films than in GeO[SiO2] films and is higher in films on a fused silica substrate than in films on a c-Si substrate for the same annealing parameters. The sizes of germanium nanocrystals formed by electron beam annealing were determined from the Raman spectra. The proposed method for obtaining amorphous nanoclusters and germanium nanocrystals in films of nonstoichiometric germanium silicate glasses using electron beam annealing can be employed to create laterally ordered arrays of amorphous nanoclusters and nanocrystals.