New selector based on zinc oxide grown by low temperature atomic layer deposition for vertically stacked non-volatile memory devices

We report on the fabrication of Schottky diodes based on n-type zinc oxide (ZnO) grown by atomic layer deposition (ALD) at low temperature (100 °C). These structures are suitable as selector elements in highly integrated non volatile memories based on crossbar architecture. The junctions are fully realized by optical lithography and the smallest investigated structures are 3 × 3 μm² area. Several metals have been tested to single out the most suitable ohmic and Schottky contact materials. The electrical characterisation shows good properties with a forward current above 10⁴ A/cm² and a rectifying ratio of 10⁵.