Partially Depleted SONOS FinFET for Unified RAM (URAM)—Unified Function for High-Speed 1T DRAM and Nonvolatile Memory

Abstract

Unified random access memory (URAM) is demonstrated for the first time. The novel partially depleted (PD) SONOS FinFET provides unified function of a high-speed capacitorless 1T DRAM and a nonvolatile memory (NVM). The combination of an oxide/nitride/oxide (O/N/O) layer and a floating-body facilitates URAM operation in PD SONOS FinFETs. An NVM function is achieved by FN tunneling into the O/N/O stack and, a 1T-DRAM function is achieved by excessive-hole accumulation in the PD body. The fabricated PD SONOS FinFET shows retention time exceeding 10 years for NVM operation and program/erase time below 6 ns for 1T-DRAM in a single-cell transistor. These two memory functions are guaranteed without disturbance between them.