Abstract
This letter presents a new 2-bit/cell contact-gated one-time-programmable (OTP) device, which is demonstrated in a 90-nm CMOS logic process. The cell is programmed by electron injection and storage in the contact-etch-stop-layer (CESL) nitride film. A novel contact gate is introduced to serve as a select transistor, which allows the cell to exhibit good immunity against program and read disturbances. The 2-bit/cell operation is achieved by selectively injecting charges into the CESL on either side of the contact gate through channel-hot-electron operation. With a unit bit area of 13.8 F 2 , this nitride-based contact-gated OTP memory is highly feasible for advanced logic applications. © 2009 IEEE.