Retention Model of TaO/HfO and TaO/AlO RRAM with Self-Rectifying Switch Characteristics.

A retention behavior model for self-rectifying TaO/HfO - and TaO/AlO -based resistive random-access memory (RRAM) is proposed. Trapping-type RRAM can have a high resistance state (HRS) and a low resistance state (LRS); the degradation in a LRS is usually more severe than that in a HRS, because the LRS during the SET process is limited by the internal resistor layer. However, if TaO/AlO elements are stacked in layers, the LRS retention can be improved.

The Role of Ti Buffer Layer Thickness on the Resistive Switching Properties of Hafnium Oxide-Based Resistive Switching Memories.

Ti/HfO-based resistive random access memory (RRAM) has been extensively investigated as an emerging nonvolatile memory (NVM) candidate due to its excellent memory performance and CMOS process compatibility. Although the importance of the role of the Ti buffer layer is well recognized, detailed understanding about the nature of Ti thickness-dependent asymmetric switching is still missing. To realize this, the present work addresses the effects of Ti buffer layer thickness on the switching properties of TiN/Ti/HfO/TiN 1T1R RRAM.

Polarity reversion of the operation mode of HfO2-based resistive random access memory devices by inserting Hf metal layer.

The reversion of polarity within bipolar resistive switching operation occurs in Pt/HfO2/TiN and Pt/Hf/HfO2/TiN resistive random access memory devices. This reversion of voltage polarity is the result of interface generation which induces a conduction mechanism transformation from Poole-Frenkel emission to space charge limited current mechanism. To prove the reversion of polarity, this study uses curve fitting of I-V relations to verify the conduction mechanism theoretically and physical analysis to verify the oxygen ion distribution practically.

Enhanced nanoscale resistive switching memory characteristics and switching mechanism using high-Ge-content Ge0.5Se0.5 solid electrolyte.

We demonstrate enhanced repeatable nanoscale bipolar resistive switching memory characteristics in Al/Cu/Ge0.5Se0.5/W, as compared with Al/Cu/Ge0.

Excellent resistive memory characteristics and switching mechanism using a Ti nanolayer at the Cu/TaOx interface.

Excellent resistive switching memory characteristics were demonstrated for an Al/Cu/Ti/TaOx/W structure with a Ti nanolayer at the Cu/TaOx interface under low voltage operation of ± 1.5 V and a range of current compliances (CCs) from 0.1 to 500 μA.

Formation polarity dependent improved resistive switching memory characteristics using nanoscale (1.3 nm) core-shell IrOx nano-dots.

Improved resistive switching memory characteristics by controlling the formation polarity in an IrOx/Al2O3/IrOx-ND/Al2O3/WOx/W structure have been investigated. High density of 1 × 1013/cm2 and small size of 1.3 nm in diameter of the IrOx nano-dots (NDs) have been observed by high-resolution transmission electron microscopy.

Experimental investigation of the reliability issue of RRAM based on high resistance state conduction.

In this paper, reliability issues of robust HfO(x)-based RRAM are experimentally investigated in terms of cycling ageing, temperature impact and voltage acceleration. All reliability issues can be estimated by the conduction of the high resistance state (HRS). The conduction current of the HRS exponentially increases as the square root of the applied voltage, which is well explained by 'quasi-Poole-Frenkel-type' trap assistant tunneling.