ONO ($SiO_2/Si_3N_4/SiO_2$), NON($Si_3N_4/SiO_2/Si_3N_4$)의 터널베리어를 갖는 비휘발성 메모리의 신뢰성 비교

Charge trap flash memory devices with modified tunneling barriers were fabricated using the tunneling barrier engineering technique. Variable oxide thickness (VARIOT) barrier and CRESTED barrier consisting of thin $SiO_2$ and $Si_3N_4$ dielectric layers were used as engineered tunneling barriers. The VARIOT type tunneling barrier composed of oxide-nitride-oxide (ONO) layers revealed reliable electrical characteristics; long retention time and superior endurance. On the other hand, the CRESTED tunneling barrier composed of nitride-oxide-nitride (NON) layers showed degraded retention and endurance characteristics. It is found that the degradation of NON barrier is associated with the increase of interface state density at tunneling barrier/silicon channel by programming and erasing (P/E) stress.