Thermal Stability of Metal-Silicide Nanocrystal Nonvolatile Memory with Barrier Engineered Tunnel Layers

摘要

WSi_2 nanocrystal nonvolatile memory devices were fabricated with a silicon oxide-nitride-oxide (SiO_2: 2 nm/Si_3N_4: 2 nm/SiO_2: 3 nm) tunnel layer. WSi_2 nanocrystals of 2.5 nm diameters and a density of 3.6 × 10~(12) cm~(-2) were formed using radio frequency magnetron sputtering and annealing processes. The WSi_2 nanocrystal nonvolatile memory device exhibited strong thermal stability during writing/erasing operations at temperatures up to 125℃. When the writing/erasing voltages were applied at +10 V/-10 V for 500 ms, the memory window of the initial ～2.6 V decreased by approximately 1.1 V at 25℃ and 0.4 V at 125℃ after 10~4 sec, respectively. These results show that WSi_2 nanocrystals with barrier-engineered tunnel layers are possible for application in nonvolatile memory devices.