Three-terminal solid state Cu-ion actuated analog switching devices are provided. In one aspect, a method of forming a switching device includes: depositing a channel layer on a substrate; forming a source contact and a drain contact on opposite ends of the channel layer; forming a solid electrolyte on the channel layer over the source contact and the drain contact; and depositing a gate onto the solid electrolyte, wherein the source contact, the drain contact, and the gate are three terminals of the switching device. A switching device and a method of operating a switching device are also provided.