Selector for bipolarity resistive random access memory and preparation method for the same

The invention discloses a selector for a bipolarity resistive random access memory and a preparation method for the same. The preparation method for the selector comprises steps of providing a substrate, forming a lower electrode above the substrate, forming a first metal oxide layer above the electrode, performing annealing processing on the first metal oxide layer in order to make metal atoms in the lower electrode into the first metal oxide layer to form a first metal oxide layer doped with metal atoms, forming a second metal oxide layer above the first metal oxide layer doped with the metal atoms, forming an upper electrode above the second metal oxide layer, and performing patterning on the upper electrode to form an upper electrode. The selector prepared through the method can provide higher current density, and an ISIR structure formed by connecting to the resistive random access memory in series can effectively inhibit crosstalk in an resistive random access memory array. Furthermore, the selector has a higher selection ratio and durability.