19.1 Chapter Overview
An atomic switch is a nanoionic device that controls the diffusion of metal ions and their reduction/oxidation processes in a switching operation to form/annihilate a metal atomic bridge, which in an ON state is a conductive path between two electrodes. An atomic switch works as a nonvolatile device due to an operating mechanism that requires the reduction/oxidation reaction that each occur at opposite polarities of applied bias. Since metal atoms provide a highly conductive path even if their path size is on the nanometer scale, atomic switches may enable downscaling to smaller dimensions than the 11 nm technology node.
The operation of an atomic switch was first demonstrated using a two-terminal structure, which is now widely used in applications for memories and programmable switches. Three-terminal operation was also demonstrated recently, in which the formation and annihilation of a conductive path between two electrodes is controlled by the third electrode. Three-terminal operation shows the potential for the use of atomic switches as logic devices.
The novel characteristics of atomic switches, such as their small size, low power consumption, low ON resistance and nonvolatility, will be useful in the development of future computing systems, such as nonvolatile logic systems and normally OFF computers. Novel ...