Performance boost of crystalline In-Ga-Zn-O material and transistor with extremely low leakage for IoT normally-off CPU application

Abstract

The worldwide first 100MHz dynamic oxide semiconductor RAM (DOSRAM) is successfully demonstrated using a new high-mobility crystalline In-Ga-Zn-O (IGZO) material. The new IGZO exhibits around two times carrier mobility of conventional IGZO, while still achieving an extremely low off-state leakage (I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</inf> ) at ∼10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−21</sup> A (zA) level. Attributed to DOSRAM performance improvement, 100MHz normally-off (Noff) CPU is successfully demonstrated with drastically reduced power consumption (∼94% power reduction for ARM Cortex-M0 and ∼70% power reduction for memory), making it a promising candidate for IoT application. In addition, an OS-FPGA is successfully fabricated by integration of 65nm SiFET and 60nm oxide semiconductor FET (OSFET) with an operation frequency of 360MHz. The application of the OSFET in analog circuits will also be discussed in this paper.