Fabrication of Silicon Nano-Crystals via a Hemispherically Grained Si Process

We propose a new fabrication method for silicon nano-crystals with a high density and uniform sizes via a hemispherically grained Si (HSG-Si) process. The growth reaction was investigated by varying the thickness of the substrate's amorphous Si layer, as well as the growth temperature and the reaction time. The resultant size, density, and crystallinity of Si dots were examined by using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM). The size and the density of silicon nano-crystals were observed to be greatly influenced by the thickness of the substrate's amorphous silicon film. The thinner the substrate Si layer was, the smaller and the higher the average size and the density of Si nano-crystals were, respectively. Using a 5-nm-thick amorphous Si film, silicon nano-crystals with a size of 7 nm and a density of 2.6 × 10¹¹/cm² were successfully fabricated.