Effect of annealing time on memory behavior of MOS structures based on Ge nanoparticles

Abstract

Effects of annealing time on memory characteristics of Ge nanoparticles (NPs) as floating gate of metal-oxide-semiconductor (MOS) structure are investigated in this work. First, Ge NPs at 8.5 nm-near to Si/SiO2 interface were obtained by Low Pressure Chemical Vapor Deposition (LPCVD). The morphology and dimension of these NPs was estimated by the statistic treatment of Atomic Force Microscopy images, which exhibited an homogeneous distribution of NPs over SiO2, with a main diameter of (6.72±1.97) nm and NPs-density of 1.5×1012 cm-2. For the characterization of memory properties, high-frequency Capacitive-Voltage measurements as function of annealing time were performed on the MOS structure containing these Ge NPs. The results showed a memory window of 11.92 V with an electrical charge storage density of 6.61×1012 cm-2. The Current-Voltage measurement showed a Fowler-Nordheim tunneling as the conduction mechanism of our device.