(Invited) Embedded Oxide Semiconductor Memories: A Key Enabler for Low-Power ULSI

Abstract

The progress in emerging memory featuring indium–gallium–zinc oxide semiconductor field-effect transistors (OSFETs) is overviewed. An OSFET exhibits an extremely low off-state current in the order of zeptoamperes (zA or 10-21 A). The OSFET process is embedded into a conventional CMOS process, and the OSFET is stacked over the SiFET. The OSFET-based memory achieves high speed, low voltage writing and high endurance. Using the OSFET enables low-power ULSI such as a memory with a very low refresh rate and a processor without any leakage power. Oxide semiconductor memory is a key device that enables low-power ULSI, and it can potentially be used in various applications in which battery life is crucial.