Si nanocrystals were formed by using a Au nanoscale island etching mask. A high-resolution transmission electron microscopy image showed that the Si nanocrystals were created on a SiOx layer, and the luminescence peak related to Si nanocrystals was observed in the cathodoluminescence spectrum. Capacitance-voltage measurements demonstrate a metal-insulator-semiconductor behavior with a flatband voltage shift for the Al/SiO2/nanocrystalline Si/SiO2/P-Si structures, indicative of the existence of the Si nanocrystals embedded into the SiOx layer. These results indicate that Si nanocrystals embedded into the SiOx layer can be formed by using a Au island etching mask. (C) 2004 Elsevier Ltd. All rights reserved.