Three-terminal nanometer metal switches utilizing solid electrolytes

We propose a three-terminal nanometer metal switch that utilizes a solid electrolyte where a nanoscale metal filament is stretched and retracted. Its operating principle is based on electrochemical reaction and ion migration in the electrolyte. The fabricated device is composed of a solid electrolyte layer (Cu₂S), a gate (Cu), a source (Cu), and a drain (Pt). After the Cu filament is formed between the source and the drain by applying the drain voltage, repeatable on/off switching in the drain current is obtained by controlling the gate voltage. The on/off current ratio can be as high as 10 ⁵, and the programmable cycle is around 50. Each state can be kept for up to 40 days. Since the gate is separated from the current path, the switching current can be reduced to 10 μA, which is two orders of magnitude smaller than that of a two-terminal switch. In this paper, we present the operating principle and electrical characteristics of the three-terminal switches, and discuss how suitable they are for reconfigurable circuits.