Interface-engineered reliable HfO₂-based RRAM for synaptic simulation

Abstract

O3-based interface engineering dominates implementations of analog memory and synaptic simulation using reliable Pt/HfO2/TiN RRAM.

Advances of RRAM Devices: Resistive Switching Mechanisms, Materials and Bionic Synaptic Application

“…In this review, we will present RRAM-related inorganic materials with oxides, solid electrolyte and two-dimensional (2D) materials. [9,20,75], NiO [8,12,76], TiO 2 [21,77,78], HfO 2 [60,79,80], ZnO [81][82][83], and ZrO 2 [22,84,85] are always playing main roles in materials application of RS medium. The first report of RS performance in binary metal oxides was proposed by Hickmott in 1962 [91], which demonstrated the RS characteristics of Al/Al 2 O 3 /Al device under the effect of an electric field.…”

“…Wang et al proposed an interface engineering method on ALD-based HfO 2 thin film with O 3 , which improved the performance of Pt/HfO 2 /TiN RRAM device [79]. It is reported that the best stability could be observed in the HfO 2 RRAM device with 20 pulses of O 3 treatment.…”

Self-Compliance and High Performance Pt/HfOx/Ti RRAM Achieved through Annealing

“…RRAMs based on various materials, including metal oxides [5,6], novel nanomaterials [7][8][9], and organics [10,11], have been proposed. Among them, RRAM based on hafnium oxide [12][13][14][15], which replaced SiO 2 as the gate dielectric of choice below the 45 nm node [16,17], has been widely studied due to its high switching stability. There are still many challenges to overcome before RRAMs can be used as commercial memory, such as switching uniformity, overshoot current during forming or set process, leakage current in integrated arrays, and so on [4,18].…”

Multi-Level Analog Resistive Switching Characteristics in Tri-Layer HfO2/Al2O3/HfO2 Based Memristor on ITO Electrode

“…During the application of the negative pulse train, again gradually the weak filaments formed at both interfaces. To implement more accurately synaptic efficiency, of the tri-layer TaN/HfO 2 /Al 2 O 3 /HfO 2 /ITO memristor, negative pulse, and positive depression pulse with increasing amplitude were applied for potentiation and depression characteristics [ 47 , 48 , 49 ]. For potentiation and depression, increasing the pulse amplitude from −0.6 to −1.4 V, with a −0.05 V step, and 0.8 to 1.6 V, with a 0.05 V step, respectively, was applied to each tri-layer RRAM device.…”

“…Positive synaptic weight change is observed in the IInd quadrant when Δt increases from 0 to ‒100 µs, which indicates synaptic potentiation, and negative synaptic weight change observed in the IVth quadrant when Δt varies from 0 to 100 µs is described as synaptic depression. The change of synaptic weight can be described as follows: where A + and A ‒ are the synapse maximum weights at Δt = 0, and τ + and τ ‒ are the broadening of the STDP window [ 48 ]. From Figure 6 d, it can be found that the maximum change in synaptic weight [ΔW(ΔG/G) = (G fin − G min )/G min ] for positive Δt was 98.3% and for negative Δt was −94.8%, which is very symmetric for tri-layer RRAM device.…”