Yongbian Kuang

Unipolar

In this letter, a reproducible unipolar resistive change memory (RRAM) based on TaOx was successfully fabricated through electrode design. The fabricated unipolar RRAM exhibits lower switching voltages, fast switching speed of less than 80 ns, excellent retention capabilities, and stable cycling behaviors. Moreover, the role of top-electrode material on the resistive switching mode polarity of TaOx-based RRAM was verified by comparative experiments. Analysis about the electrode effect on the resistive switching mode polarity of TaOx-based RRAM with the theory of Gibbs free energy may provide some guidelines for the design of unipolar metal-oxide-based RRAM.

\hbox{TaO}_{x}

A novel flexible polymer resistive memory device based on single-component polymer polychloro-para-xylylene (parylene-C) sandwiched between Al or Cu top electrode and W bottom electrode is presented in this letter. With 4 × 4 crossbar array, the polymer memory device is fabricated by standard photolithograph technology, due to the chemical stability and the immunity of parylene-C to the chemicals and solvents in lithographic process. The device exhibits a good memory margin of more than 107 on/off current ratio, as well as ultrafast programming/erasing speed (<;15 ns). Moreover, a good retention time of more than 2.5 × 105 s and a cycling endurance of more than 130 program-read-erase-read cycles are obtained in this polymer memory device. The successfully demonstrated performance of this polymer memory shows great potential for transparent, flexible, and high-density memory applications and hybrid integration with CMOS back-end process.

-Based Resistive Change Memory Realized With Electrode Engineering

In this letter, a reliable nonvolatile resistive switching device based on silicon monoxide (SiO) is demonstrated. The device was fabricated with a low-temperature process that can be compatible with a CMOS back-end process and attractive for 3-D memory integration. The fabricated Cu/SiO/W device was found to have a repeatable unipolar resistive switching behavior. The results show excellent on/off resistance ratio (over 104) and good retention performance. The switching mechanism of the device is analyzed by experimental data and probably can be attributed to the behaviors of copper ions in the bulk of SiO under different voltages.

Flexible Single-Component-Polymer Resistive Memory for Ultrafast and Highly Compatible Nonvolatile Memory Applications

This letter reports a novel single-component organic-memory cell based on oxotitanium phthalocyanine (TiOPc) material. The device can achieve good resistive-switching performance such as a high on/off current ratio of about 104, large read signal window (4 V), and good retention (4 h at 1-V read voltage). The organic-memory cell exhibits excellent thermal stability above 525 K due to the thermal robustness of TiOPc, which indicates its potential for hybrid integration with CMOS technology at the back-end process and flexible electronics system. The current-voltage characteristics are comprehensively investigated, and a possible mechanism is proposed and well fitted with the experimental data. The results show that the trap-filling space-charge-limited conduction with TiOPc charge confinement and the electrochemical reaction at the Al/TiOPc interface can elucidate the switching behavior of the memory cell.

Unipolar Resistive Switch Based on Silicon Monoxide Realized by CMOS Technology

In this paper, the resistive switching behavior of a single-component-polymer resistive memory device based on polychloro-para-xylylene (parylene-C) is comprehensively studied. With the excellent chemical stability and high process compatibility of parylene-C, an 8 × 8 crossbar array with a sandwiched structure of parylene-C and active electrodes is fabricated, which can be integrated in the CMOS back-end process and shows great potentials for future transparent, low-cost, flexible, and high-density nonvolatile memory applications. This organic memory device exhibits excellent performance with a 107 ON/OFF current ratio, nanosecond set/reset speed, and low switching voltages, as well as good retention and cycling endurance behaviors. The switching mechanism is systematically investigated with the comparison between active electrodes (Al, Cu, or Ag) and an inert electrode (Pt), as well as the dependence on temperature and device area.

Novel Thermally Stable Single-Component Organic-Memory Cell Based on Oxotitanium Phthalocyanine Material

In this paper, a unipolar resistive change memory (RRAM) based on TaOx has been successfully fabricated. The fabricated unipolar RRAM exhibits lower switching voltages without any forming process, fast switching speed, good retention performance even under high temperature baking and stable cycling behavior. Multilevel of data storage can also be achieved by voltage control during the reset process. In addition, the current compliance (CC) effect on the behavior of the device has also been investigated. Based on the measurements, the switching voltages/currents and the low resistance state (LRS) of the device have little dependence on CC, which can effectively simplify RRAM circuit design. Resistive switching polarity dependence on the bi-layer structure has also been analyzed with comparative experiments.

Resistive Switching in Organic Memory Device Based on Parylene-C With Highly Compatible Process for High-Density and Low-Cost Memory Applications

The organic resistance memories show great potentials for future flexible applications. In this paper the main challenges and typical recent progress of the organic resistance memory devices are discussed. A kind of single-component polymer resistance memory device based on polychloro-paraxylylene (parylene-C) is focused, with excellent chemical stability and high CMOS process compatibility as well as further reduction of operation current, which is promising for future information storage in flexible systems.

Forming-Less Unipolar TaOx-Based RRAM with Large CC-Independence Range for High Density Memory Applications

In summary, a novel RRAM with the structure of Cu/SixOyNz/W was first fabricated and its characteristics are thoroughly investigated. The new device exhibited low switching voltages and low reset currents, demonstrating its potential for low-power applications. Repeatable unipolar resistive switching characteristics in terms of high off/on resistance ratio and good retention capability were observed. The switching mechanism of the device was analyzed and can be explained by the formation and rupture of vacancy-filaments.

Resistive switching in organic memory devices for flexible applications

This paper has reported a programmable switch composed of copper-doped-SiO2 sandwiched between Cu top electrode and inert W bottom electrode. Reproducible rectifying-like I-V performance was found in the device with top electrode (TE), while with regard to the cell without TE, no rectifying-like I-V characterization was observed. This rectifying-like I-V curve is properly caused by electrode contact. To further prove the effect of TE, RON retention behavior of the device with TE and without TE were investigated. The testing results clearly showed that the RON retention property of device with TE was worse than that without TE. We propose a model for the interface between top electrode and copper-doped-SiO2 to interpret this rectifying-like performance, which indicates that interface rectifying-like effect emerges when on-resistance is comparable with the resistance of diode-like junction between metal contact and resistive-material. The results suggest that optimizing interface condition or adjusting resistive material with large on-resistance is essential for robust MIM RRAM design.

A novel nitrogen-doped SiO x resistive switching memory with low switching voltages

A novel polymer (organic) resistive memory device with the structure of W/parylene+Au/Al is presented in this paper. The organic memory device exhibits not only high scalability but also good compatibility with CMOS back-end process, for parylene is immune to the lithographic solvents. Moreover, parylene film could be fabricated by chemical vapor deposition (CVD) instead of spin-coating, thus the quality and uniformity of the film can be improved. The device exhibits good nonvolatile memory characteristics, including low operating voltage (1.5 V / −3 V) and good retention capability (29000 s). A possible switching mechanism is also proposed and supported by the experimental data. The device shows great potentials for flexible, stackable and high-density memory applications.