The development of an enhancement-mode single-transistor SONOS cell in 0.13µm technology

An enhancement-mode Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) device has been developed in 0.13µm technology platform. The single-transistor (1-T) SONOS device in NOR Flash memory array utilizes n-channel cells. The development of 1-T SONOS is not an easy feat due to many disturbs experienced by the cells during operation. By the manipulation of program/erase mechanisms and operational conditions, all disturbs can be suppressed to the manageable level. The preferred program method is by Channel Initiated Secondary Electron (CHISEL) while F-N tunneling is utilized in erase operation. Silicon-Oxynitride (SiOxNy) film is chosen as the ONO trapping layer because of its superior data retention performance in comparison to the silicon nitride (Si3N4). Characterization results of SONOS cells, with ONO film stack 26A tunnel-oxide/105A SiOxNy/42A top-oxide, show reasonably good program speed, erase speed, data retention, endurance, and free or has minimal effect from all disturbs.