Metal-insulator-semiconductor (MIS) capacitors, having 1-, 2-, or 3-layer Ge nanocrystals (NCs) in SiO2/SiNx dielectrics for charge storage application have been fabricated and characterized. Multi-stack Ge NCs were fabricated by thermal-annealing the amorphous SiGeO/SiNx multilayers deposited with a plasma-enhanced chemical vapor deposition (PECVD) system. Micro-Raman spectra and images of transmission electron microscopy (TEM) demonstrated the presence of Ge NCs after annealing. More holes trapping and storage than electrons were exhibited in capacitance-voltage (C-V) hysteresis curves at room temperature. Increasing the number of layer for Ge NCs in SiO2/SiNx dielectrics from 1 through 2 to 3 improved the memory window from 0.3 through 0.5 to 2.3 V as obtained by C-V hysteresis curves. The current density-voltage (J-V) curves of MIS capacitors exhibited the multi-peak form at the higher negative voltages due to the transient displacement current from the substrate to the Ge NCs. (C) 2009 Elsevier Ltd. All rights reserved.