Investigation of Ge nanocrytals in a metal-insulator-semiconductor structure with a HfO2/SiO2 stack as the tunnel dielectric -: art. no. 113105

A metal-insulator-semiconductor (MIS) structure containing a HfO2 control gate, a Ge nanocrystal-embedded HfO2 dielectric and a HfO2/SiO2 stack layer as tunnel oxide, was fabricated by an electron-beam evaporation method. High-resolution transmission electron microscopy study revealed that the HfO2/SiO2 stack layer minimized Ge penetration, leading to the formation of Ge nanocrystals that are self-aligned between the tunnel oxide and the capping HfO2 layer. Influence of different annealing conditions on the formation and distribution of Ge nanocrystals was studied. Current-voltage (I-V) and capacitance-voltage (C-V) measurements revealed promising electrical characteristics of the MIS structure, and relatively high stored charge density of 10(12) cm(-2) was achieved. (C) 2005 American Institute of Physics.