Influence of nucleation parameters in the spatial distribution of the Ge nanocrystals formed by LPCVD

In this work, we study the nucleation stage that precedes the growth of Ge nanostructure (ns) on SiO2 matrix by low-pressure chemical vapor deposition (LPCVD). The preliminary results show that it is possible to form Ge nanocrystals (NCs) without previous silicon nuclei formation and the role that these nuclei plays would be in increasing the density of Ge NCs. The influence of the nucleation parameters on size and spatial distribution of Ge ns is analyzed. Results from atomic force microscopy (AFM) show that a high ns density of 3.6×1010 cm−2, with a mean size of 11 nm, can be obtained with the set of the following parameters: 600 °C/666.5 Pa/10 sccm SiH4. Results of high-resolution transmission electron microscopy (HRTEM) show that obtained Ge ns are NCs.