(Invited) Atom Switch Technology for Low-Power Nonvolatile Logic Application
Authors: Tada Munehiro , Sakamoto Toshitsugu , Miyamura Makoto , Banno Naoki , Okamoto Koichiro , Hada Hiromitsu 
Published: February 2020

With the increasing functions in digital circuit, flexibility and energy-efficiency play important roles in addressing future mobile/cloud computing systems. Scaling of CMOS devices and interconnects has contributed to high performance and low power operation of ULSI devices. Due to excessive stand-by power accompanying device shrinking, further scaling is experiencing serious roadblocks, and in near future, scaling will face a physical limit of the device dimension. One of the solutions to enhance device performance without scaling is to introduce “More than Moore” devices, which are integrated on CMOS without increasing the chip-size. Especially, resistive switching devices, such as magnetic random-access memory [1], phase-change memory [2], and electrochemical switch [3-5], have attracted much attention because of their potential for use in not only memory but also logic application.

Atom switch is an electrochemical resistive-change device categorized in the cation type [4]. The electrochemical phenomenon is nonvolatile and based on electrolysis of the Cu electrode to produce a precipitation of Cu between the electrodes, which realizing a high ON/OFF conductance ratio. Previously, we reported a replacement of the SRAM-based switch with atom switch integrated in Cu-BEOL (Fig.2) [6]. An elimination of the forming process and high ON/OFF-state reliabilities have been realized by introducing a polymer solid-electrolyte (PSE) [7], a complementary atom switch (CAS) [8] and alloy electrodes [9].

As compared to a two-terminal device, a three-terminal device is advantageous for the logic application since the separation of the programming line and signal transfer line simplifies circuit design and reduces the layout area. In this paper, a three-terminal resistive-change device featuring the resistive-change junctions coupled with the diode-inserted gate is discussed.

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