Resistive-memory embedded unified RAM (R-URAM)

A disturb-free unified RAM (URAM) is demonstrated. It consists of a nonvolatile memory (NVM) and a capacitorless dynamic random access memory (DRAM) in a single-cell transistor. The NVM function is achieved by the resistive switching of an Al₂O₃ film, and the capacitorless DRAM operation is attained by hole accumulation in a floating body. A property of resistive switching-an abrupt change of the bistable resistance state at a specific voltage-permits a high level of immunity to disturbances between NVM and capacitorless DRAM (1T-DRAM) operations compared to the previously proposed URAM whose NVM characteristics originate from charge trapping in the oxide/nitride/ oxide layer.