[paper] Future of Ultra-Low Power SOTB CMOS

Nobuyuki Sugii¹, Shiro Kamohara², Makoto Ikeda³

The Future of Ultra-Low Power SOTB CMOS Technology and Applications

NANO-CHIPS 2030. The Frontiers Collection. Springer, Cham

DOI: 10.1007/978-3-030-18338-7_6

1.Hitachi, Ltd.Tokyo, Japan
2.Renesas Electronics Corp.Tokyo, Japan
3.The University of Tokyo, Japan

Abstract: Ultra-low power technology has drawn much attention recently as the number of connecting (Internet-of-Things) devices rapidly increases. The silicon-on-thin-buried oxide (SOTB) technology is a CMOS device technology that uses fully depleted silicon-on-insulator (FDSOI) transistors with a thin buried oxide layer enabling enhanced back-bias controllability and that can be monolithically integrated with the conventional bulk CMOS circuits. It can significantly reduce both the operation and the standby powers by taking advantage of low-voltage operation and back-biasing, respectively. In this chapter, advantages of the SOTB technology in terms of ultra-low power, circuits design and chip implementation examples including ultra-low power micro-controllers operating with harvested power, reconfigurable logic circuits, analog circuits, are reviewed, and a future perspective is shown.

Fig.: Schematic cross section of SOTB transistors. Hybrid bulk transistors are shown. SOTB  transistors are used in low-voltage (< ~1.5 V) logic and analog circuits including SRAMs. Bulk  transistors are used in peripheral, ESD-protection, high-voltage analog and power circuits, on-chip,  flash memory, and reuse of legacy circuits

Acknowledgements: The part of the work, especially on developing the SOTB technology by the Low-power Electronics Association and Project (LEAP), is supported by the Ministry of Economy, Trade and Industry (METI) and the New Energy and Industrial Technology Development Organization (NEDO). Part of the chip fabrication by the universities is done under a support of VLSI Design and Education Center (VDEC) in collaboration with Renesas Electronics Corporation, Cadence Corporation, Synopsys Corporation and Mentor Graphics Corporation.