Electrical properties of multilayer silicon nano-crystal nonvolatile memory

Nonvolatile memories with triple layers silicon nanocrystals have been fabricated with conventional CMOS technology. In this paper, the program and erase performance and reliability of nanocrystal nonvolatile memories (NCNVMs) with triple layers of nanocrystals are investigated. Experiment result indicates that the nanocrystals in the triple layers NCNVMs are difficult to be fully charged during program process for the second and third layers nanocrystals at low applied gate voltage. The program and erase transient characteristics for the triple NCNVMs is also measured at various programming times. The charges mainly trapped at the first layer nanocrystal below 1 ms, and then transferred to the second and third layer silicon nanocrystal as increasing program time further more. The reliability performance is analyzed by endurance measurement. The memory window has little degradation after 10⁴ cycling.