Selection device for use in bipolar resistive memory and manufacturing method therefor

A selection device for use in a bipolar resistive memory, comprising: a lower electrode (21) formed on a substrate (20); a first metal oxide layer (22) doped with metal atoms formed above the lower electrode (21); a second metal oxide layer (23) formed above the first metal oxide layer (22) doped with metal atoms; and an upper electrode layer (24) formed above the second metal oxide layer (23). The electrical current density of the selection device is increased.