A semiconductor device with an array of vertically stacked electrochemical random-access memory (ECRAM) devices, includes holes formed in a vertical stack of horizontal electrodes. The horizontal electrodes are horizontally aligned and stacked vertically at different vertical levels within the vertical stack and separated by first fill layers. The semiconductor device includes a stack deposition, including a channel layer, and an electrolyte layer, formed over the vertical stack and holes. Selector layers fill holes. The selector layers include an inner selector layer and outer selector layers. The channel layer, the electrolyte layer and outer selector layers are recessed to the inner selector layer and a fill layer is deposited over the vertical stack. The fill layer has been reduced down to the top of the inner selector layer.