Analysis of charge loss in nonvolatile memory with multi-layered SiC nanocrystals

Abstract

A nonvolatile memory device with multilayered SiC nanocrystals for long-term data storage was fabricated, and its electrical properties were analyzed. The average size and density of the SiC nanocrystals, which were formed between the tunnel and control oxide layers, were approximately 5 nm and 2x10(12) cm(-2), respectively. The memory window of nonvolatile memory with the multilayer of SiC nanocrystals was about 2.5 V after program and erase voltages of +/- 12 V were applied for 500 ms, and then it was maintained at about 1.1 V for 10(5) s at 75 degrees C. The activation energy estimated from charge losses of 25% to 50% increased from 0.03 to 0.30 eV, respectively. The charge loss could be caused by a Pool-Frenkel current of holes and electrons between the SiC quantum dots and the carrier charge traps around the SiC nanocrystals embedded in SiO2 or the degradation effect of the tunnel oxide by stress induced leakage current.