Characterization of germanium nanocrystal charge storage memory structures

Abstract

Memory effect has been observed in our fabricated tri-layer insulator structure, with Ge nanocrystals embedded in an amorphous SiO2 matrix. The tri-layer insulator structure consists of a thin tunnel oxide (2.5 to 10 nm) grown by rapid thermal oxidation (RTO), followed by a radio frequency (rf) co-sputtered (Ge+SiO2) middle layer (3 to 20 nm) and a third layer of rf sputtered capping SiO2 (50 nm). Rapid thermal annealing (RTA) was subsequently performed at 1000 A?C for 300 s for the synthesis of the Ge nanocrystals. Electrical characterization techniques such as Transmission Electron Microscppy (TEM), Secondary Ion Mass Spectroscopy (SIMS), conductance measurements and charge retention experiment will be performed on the device. Effects of varying thickness in the individual tri-layer on its charge storage, charge retention and density of interface traps will be discussed.