Non-volatile memory application of glancing angle deposition synthesized Er2O3 capped SnO2 nanostructures

Abstract

An Er2O3 capped SnO2 nanostructure (NS) based memory device was synthesized on Si substrate by glancing angle deposition technique. Field emission scanning electron microscopy and transmission electron microscopy were used to verify the formation of the Er2O3 capped SnO2 NS. The Er2O3 capped SnO2 NSs were polycrystalline in nature as obtained from selected area electron diffraction analysis. Au metal contact was deposited over the Er2O3 capped SnO2 NS to fabricate a Au/Er2O3–SnO2/Si memory device. The Er2O3 capped SnO2 memory device showed a higher memory window of 1V, and higher charge storage capability (0.7 × 1010 cm−2) compared to a bare SnO2 NW memory device. The Er2O3 capped SnO2 device also exhibited good endurance over 500 programming/erasing cycles as well as good retention properties (measured for 103s) with charge loss as low as 1.86%. The programme/erase process of the Er2O3 capped SnO2 device is explained with respect to a band diagram. The fabricated Er2O3 capped SnO2 NS is a Type-II heterostructure with Er2O3 acting as a charge trapping layer. Such a heterostructure type is a good candidate for non-volatile memory applications.