Formation of germanium nanocrystals by rapid thermal oxidizing SiGeO layer for nonvolatile memory application

Abstract

A new method to fabricate Ge nanocrystals by rapid thermal oxidizing SiGeO layer for nonvolatile memory application was investigated in this study. The oxidation process nucleated the Ge nanocrystals embedded in the dielectric layer was clearly observed by transmission electron microscope analysis. Moreover, an over-oxidation phenomenon for the formation of GeO2 in this work was found at higher temperature oxidation according to the X-ray photoelectron spectroscopy analysis. The obvious memory window was found in the capacitance-voltage hysteresis curve, and the program efficiency of holes was superior to electrons due to the electronic affinity of GeO2 smaller than silicon substrate for a structure of Ge nanocrystals surrounded with GeO2 layer. Furthermore, the Ge nanocrystals surrounded with GeO2 layer structure has good retention time and endurance. © 2007 Elsevier B.V. All rights reserved.