Formation of TaN nanocrystals embedded in silicon nitride by phase separation methods for nonvolatile memory applications

TaN nanocrystals (NCs) embedded in silicon nitride were investigated as a new charge-trapping layer of a silicon-oxide-nitride-oxide-silicon-type nonvolatile memory device. After annealing at 900 degrees C, TaN NCs with average size of 3.5 nm were formed by the phase separation method. Compared with a control sample without NC, memory devices with TaN NCs exhibit superior memory characteristics, such as a larger window of capacitance-voltage hysteresis and a lower charge loss rate. The improvement can be explained by the formation of high density TaN NCs with a deeper trap energy level. (c) 2007 American Institute of Physics.