Resistive switching characteristics of NiO films deposited on top of W or Cu pillar bottom electrodes

This paper demonstrates the feasibility of resistive switching memory elements integrating a nickel oxide film deposited on top of a pillar bottom electrode. The unipolar switching was investigated over a wide temperature range (25 to 125 °C) on samples integrating either W or Cu plugs with diameters ranging from 1 down to 0.18 μm. The switching characteristics and scaling trends of various fabricated memory elements were compared to select the best bottom electrode contact. It was shown that NiO layers deposited on top of W-plugs exhibited the most satisfactory electrical characteristics for future high density memory devices. Their reliability performances in terms of endurance and retention were subsequently studied by using either quasi-static or pulse programming modes. Set operations with short (10 to 20 ns) and low amplitude (around 2 V) voltage pulses were also demonstrated.