Controllable Formation of Nanofilaments in Resistive Memories via Tip‐Enhanced Electric Fields

Resistive random access memory (ReRAM) has a great potential to be the next-generation non-volatile memory device. However, the random nucleation and growth of conductive filaments (CFs) in ReRAM causes the low reliability in switching behaviors, leading to difficulties in its practical application. This study demonstrates that manipulating electric fields in ReRAM via a structured electrode can provide the controllable formation of CFs. Ag pyramids that have a high-quality tip prepared via the template-stripping method generate highly enhanced electric fields at the tip. Because the tip-enhanced electric fields can facilitate the ionization of Ag atoms and their migration along the electric fields, the nucleation and growth of CFs occurs predominantly at the tip. The CFs in ReRAM are directly observed using electron microscopy and it is confirmed that the CFs are formed only at the tip. The resulting ReRAM exhibits low and reliable SET/RESET voltages (0.48 V ± 0.02 V and 0.15 V ± 0.06 V, respectively). Moreover, its endurance and retention time are highly improved, compared to those devices that are based on conventional geometry. Thus, this approach can encourage creating high-performance ReRAM.

[1]  Sang‐Hyun Oh,et al.  Fabrication of Smooth Patterned Structures of Refractory Metals, Semiconductors, and Oxides via Template Stripping , 2013, ACS applied materials & interfaces.

[2]  Shimeng Yu,et al.  Metal–Oxide RRAM , 2012, Proceedings of the IEEE.

[3]  Milan Mrksich,et al.  Nanopatterned Substrates Increase Surface Sensitivity for Real-Time Biosensing , 2013 .

[4]  Achim Hartschuh,et al.  Tip-enhanced near-field optical microscopy. , 2008, Chemical Society reviews.

[5]  Peng Jiang,et al.  Templated Fabrication of Periodic Metallic Nanopyramid Arrays , 2007 .

[6]  Sang‐Hyun Oh,et al.  Ultrasmooth Patterned Metals for Plasmonics and Metamaterials , 2009, Science.

[7]  H. Hwang,et al.  Improved Switching Variability and Stability by Activating a Single Conductive Filament , 2012, IEEE Electron Device Letters.

[8]  Run‐Wei Li,et al.  A multilevel memory based on proton-doped polyazomethine with an excellent uniformity in resistive switching. , 2012, Journal of the American Chemical Society.

[9]  Ee Wah Lim,et al.  Conduction Mechanism of Valence Change Resistive Switching Memory: A Survey , 2015 .

[10]  Siddharth Gaba,et al.  Nanoscale resistive memory with intrinsic diode characteristics and long endurance , 2010 .

[11]  Yoshio Nishi,et al.  Ti-electrode effects of NiO based resistive switching memory with Ni insertion layer , 2012 .

[12]  Cheol Seong Hwang,et al.  Highly Improved Uniformity in the Resistive Switching Parameters of TiO2 Thin Films by Inserting Ru Nanodots , 2013, Advanced materials.

[13]  Gang Wang,et al.  Forming Free Bipolar ReRAM of Ag/a-IGZO/Pt with Improved Resistive Switching Uniformity Through Controlling Oxygen Partial Pressure , 2015, Journal of Electronic Materials.

[14]  Qi Liu,et al.  Real‐Time Observation on Dynamic Growth/Dissolution of Conductive Filaments in Oxide‐Electrolyte‐Based ReRAM , 2012, Advanced materials.

[15]  Victor Yi-Qian Zhuo,et al.  Improved Switching Uniformity and Low-Voltage Operation in ${\rm TaO}_{x}$-Based RRAM Using Ge Reactive Layer , 2013, IEEE Electron Device Letters.

[16]  W. Lu,et al.  CMOS compatible nanoscale nonvolatile resistance switching memory. , 2008, Nano letters.

[17]  J Joshua Yang,et al.  Memristive devices for computing. , 2013, Nature nanotechnology.

[18]  Gunuk Wang,et al.  Conducting-interlayer SiOx memory devices on rigid and flexible substrates. , 2014, ACS nano.

[19]  Wuhong Xue,et al.  Thermally Stable Transparent Resistive Random Access Memory based on All‐Oxide Heterostructures , 2014 .

[20]  Yiwei Liu,et al.  Observation of Conductance Quantization in Oxide‐Based Resistive Switching Memory , 2012, Advanced materials.

[21]  Keon Jae Lee,et al.  Reliable control of filament formation in resistive memories by self-assembled nanoinsulators derived from a block copolymer. , 2014, ACS nano.

[22]  Young Jae Kwon,et al.  Pt/Ta2O5/HfO2−x/Ti Resistive Switching Memory Competing with Multilevel NAND Flash , 2015, Advanced materials.

[23]  Lukas Novotny,et al.  Individual Template-Stripped Conductive Gold Pyramids for Tip-Enhanced Dielectrophoresis , 2014, ACS photonics.

[24]  Chang-Soo Han,et al.  Use of dielectrophoresis in the fabrication of an atomic force microscope tip with a carbon nanotube: a numerical analysis , 2005, Nanotechnology.

[25]  Seung Ryul Lee,et al.  Self‐Limited Switching in Ta2O5/TaOx Memristors Exhibiting Uniform Multilevel Changes in Resistance , 2015 .

[26]  Sang‐Hyun Oh,et al.  Engineering metallic nanostructures for plasmonics and nanophotonics , 2012, Reports on progress in physics. Physical Society.

[27]  Jong-Ho Lee,et al.  32 × 32 Crossbar Array Resistive Memory Composed of a Stacked Schottky Diode and Unipolar Resistive Memory , 2013 .

[28]  Fu-Chien Chiu,et al.  Electrical conduction mechanisms of metal∕La2O3∕Si structure , 2005 .

[29]  Wilfried Vandervorst,et al.  Three-dimensional observation of the conductive filament in nanoscaled resistive memory devices. , 2014, Nano letters.

[30]  H. Hwang,et al.  Excellent Switching Uniformity of Cu-Doped $\hbox{MoO}_{x}/\hbox{GdO}_{x}$ Bilayer for Nonvolatile Memory Applications , 2009, IEEE Electron Device Letters.

[31]  Yuchao Yang,et al.  Observation of conducting filament growth in nanoscale resistive memories , 2012, Nature Communications.

[32]  Hyunsang Hwang,et al.  Accelerated Publication: Improved switching uniformity of a carbon-based conductive-bridge type ReRAM by controlling the size of conducting filament , 2011 .

[33]  Martin Tajmar,et al.  The dielectrophoretic attachment of nanotube fibres on tungsten needles , 2007 .

[34]  He Tian,et al.  In Situ Tuning of Switching Window in a Gate‐Controlled Bilayer Graphene‐Electrode Resistive Memory Device , 2015, Advanced materials.

[35]  Qi Liu,et al.  Controllable growth of nanoscale conductive filaments in solid-electrolyte-based ReRAM by using a metal nanocrystal covered bottom electrode. , 2010, ACS nano.

[36]  M. Kozicki,et al.  Electrochemical metallization memories—fundamentals, applications, prospects , 2011, Nanotechnology.

[37]  S. Menzel,et al.  Physics of the Switching Kinetics in Resistive Memories , 2015 .

[38]  Byung Joon Choi,et al.  Purely Electronic Switching with High Uniformity, Resistance Tunability, and Good Retention in Pt‐Dispersed SiO2 Thin Films for ReRAM , 2011, Advanced materials.

[39]  A. Bid,et al.  Temperature dependence of the resistance of metallic nanowires of diameter≥15nm: applicability of Bloch-Grüneisen theorem , 2006, cond-mat/0607674.

[40]  R. Dittmann,et al.  Redox‐Based Resistive Switching Memories – Nanoionic Mechanisms, Prospects, and Challenges , 2009, Advanced materials.

[41]  Wei Wang,et al.  Improved Resistive Switching Uniformity in $ \hbox{Cu/HfO}_{2}/\hbox{Pt}$ Devices by Using Current Sweeping Mode , 2011, IEEE Electron Device Letters.