Abstract
In this letter, TiN nanocrystals three-dimensionally embedded in the Si 3 N 4 formed by spinodal phase segregation was investigated as the discrete charge-trapping layer in a metal - oxide - nitride - oxide - silicon structure for nonvolatilememory applications. TiN-nanocrystal formation was verified by X-ray diffraction analysis while the 3-D distribution of nanocrystals in the Si 3 N 4 film was confirmed by transmission electron microscopy with the average size of 5.1 nm and a density of 9.8 × 1011 cm -2 . The promising memory performance was evidenced by the large memory window of 1.81 V with ± 4-V program/erase voltage, the high operation speed of 1.52-V threshold-voltage shift by programming at +4 V for 10 ms, the negligible memorywindow degradation up to 10 5 operation cycles, and 11% charge loss after ten-year operation.Most importantly, the charge-storage structure can be formed by a cosputtering pproach which is simple and fully compatible with existent ultralarge scale integration technology. © 2009 IEEE.