Impact of Bottom Electrode Roughness on the Analog Switching Characteristics in Nanoscale RRAM Array

Introduction: Intrinsic resistive switching properties of Pt/TiO2-x/TiO2/Pt crossbar memory array has been examined using the crossbar (4×4) arrays fabricated by using DC/RF sputtering under specific conditions at room temperature. Materials and Methods: The growth of filament is envisaged from bottom electrode (BE) towards the top electrode (TE) by forming conducting nano-filaments across TiO2/TiO2-x bilayer stack. Non-linear pinched hysteresis curve (a signature of memristor) is evident from I-V plot measured using Pt/TiO2-x /TiO2/Pt bilayer device (a single cell amongst the 4×4 array is used). It is found that the observed I-V profile shows two distinguishable regions of switching symmetrically in both SET and RESET cycle. Distinguishable potential profiles are evident from I-V curve; in which region-1 relates to the electroformation prior to switching and region-2 shows the switching to ON state (LRS). It is observed that upon reversing the polarity, bipolar switching (set and reset) is evident from the facile symmetric pinched hysteresis profile. Obtaining such a facile switching is attributed to the desired composition of Titania layers i.e. the rutile TiO2 (stoichiometric) as the first layer obtained via controlled post annealing (650oC/1h) process onto which TiO2-x (anatase) is formed (350oC/1h). Results: These controlled processes adapted during the fabrication step help manipulate the desired potential barrier between metal (Pt) and TiO2 interface. Interestingly, this controlled process variation is found to be crucial for measuring the switching characteristics expected in Titania based memristor. In order to ensure the formation of rutile and anatase phases, XPS, XRD and HRSEM analyses have been carried out. Conclusion: Finally, the reliability of bilayer memristive structure is investigated by monitoring the retention (104 s) and endurance tests which ensured the reproducibility over 10,000 cycles.

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Electrical Properties of Ag/In2O3/M (M = LaNiO3, Pt) Devices for RRAM Applications

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.209.94 ◽

2013 ◽

Vol 209 ◽

pp. 94-97

Author(s):

Bhaumik V. Mistry ◽

Utpal S. Joshi ◽

S.J. Trivedi ◽

U.N. Trivedi ◽

R. Pinto

Keyword(s):

Bottom Electrode ◽

Pulsed Laser ◽

Grazing Incidence ◽

Resistance Switching ◽

Binary Oxide ◽

Laser Deposition ◽

Oxide Materials ◽

Cross Sectional ◽

New Class ◽

Switching Characteristics

Resistance switching properties of nanostructured In2Subscript textO3 films grown on Pt and LaNiO3 (LNO) bottom electrodes have been investigated. High quality In2O3/LNO/SiO2 and In2O3/Pt/Ti/SiO2/Si heterostructures were grown by pulsed laser deposition. High purity Ag was thermally evaporated on In2O3 active layer to form top electrode. The Ag/In2O3/M (M = LNO, Pt) structure was characterized by grazing incidence XRD, AFM and cross sectional SEM. Pollycrystalline growth of oxides LNO and In2O3 was confirmed by GIXRD, where as AFM show nanostructured growth with smooth surface morphology. Two terminal I-V characteristics showed reproducible hysteresis suggesting two distinct resistance states in the film. Typical resistance switching ratio (Ron/Roff) of the order of 113 % and 72% have been estimated for In2O3 device grown on LNO and Pt substrates, respectively. The observed resistance switching characteristics offers lot of promise for new class of binary oxide materials with oxide (LNO) as bottom electrode leading to better suitability for nanoelectronics RRAM devices.

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Multilevel Switching Characteristics of Si3N4-Based Nano-Wedge Resistive Switching Memory and Array Simulation for In-Memory Computing Application

Electronics ◽

10.3390/electronics9081228 ◽

2020 ◽

Vol 9 (8) ◽

pp. 1228 ◽

Cited By ~ 3

Author(s):

Dong Keun Lee ◽

Min-Hwi Kim ◽

Suhyun Bang ◽

Tae-Hyeon Kim ◽

Sungjun Kim ◽

...

Keyword(s):

Resistive Switching ◽

Bottom Electrode ◽

Circuit Simulation ◽

Random Access ◽

Ammonium Hydroxide ◽

Successful Implementation ◽

Resistive State ◽

Set Switching ◽

Switching Characteristics ◽

Line Resistance

In this research, nano-wedge resistive switching random-access memory (ReRAM) based on a Si3N4 switching layer and silicon bottom electrode was fabricated, and its multilevel switching characteristics were investigated. The wedge bottom electrode was formed by a tetramethyl ammonium hydroxide (TMAH) wet-etching process. The nano-wedge ReRAM was demonstrated to have different reset current levels by varying the compliance currents. To explain the effect of modulating the compliance currents, the switching characteristics of both the SET and RESET behaviors were shown. After measuring the device under four different compliance currents, it was proved to have different current levels due to an inhibited resistive state after a SET switching process. Furthermore, SPICE circuit simulation was carried out to show the effect of line resistance on current summation for the array sizes of 8 × 8 and 16 × 16. These results indicate the importance of minimizing the line resistance for successful implementation as a hardware-based neural network.

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Effects of a Nb nanopin electrode on the resistive random-access memory switching characteristics of NiO thin films

Nanoscale ◽

10.1039/c8nr02986e ◽

2018 ◽

Vol 10 (28) ◽

pp. 13443-13448 ◽

Cited By ~ 7

Author(s):

Yoonho Ahn ◽

Hyun Wook Shin ◽

Tae Hoon Lee ◽

Woo-Hee Kim ◽

Jong Yeog Son

Keyword(s):

Thin Films ◽

Bottom Electrode ◽

Random Access ◽

Random Access Memory ◽

Resistive Random Access Memory ◽

Access Memory ◽

Memory Switching ◽

Switching Characteristics

We report the effects of bottom electrode shapes on resistive random-access memory (RRAM) devices composed of Nb (bottom electrode)/NiO (dielectric)/Nb (top electrode) structures.

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Electrical Switching Characteristics of Nitrogen Doped Ge2Sb2Te5 Based Phase Change Random Access Memory Cell

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.21 ◽

2007 ◽

Vol 124-126 ◽

pp. 21-24 ◽

Cited By ~ 1

Author(s):

Myoung Sub Kim ◽

Jin Hyung Jun ◽

Jin Ho Oh ◽

Hyeong Joon Kim ◽

Jae Sung Roh ◽

...

Keyword(s):

Phase Change ◽

Nitrogen Doping ◽

Bottom Electrode ◽

Random Access ◽

Memory Cell ◽

Dynamic Resistance ◽

Electrical Switching ◽

Nitrogen Doped ◽

Electrode Contact ◽

Switching Characteristics

Ge2Sb2Te5 (GST) has been widely studied for PRAM as reversible phase change material. GST is expected to reduce RESET (crystalline → amorphous) operation power, which is one of important issues for PRAM technology. In order to investigate the effect of nitrogen doping on electrical switching characteristics, we fabricated two kinds of PRAM cells with nitrogen-doped (N-doped) and un-doped GST, which were different bottom electrode contact size (0.80~1.00 ). N-doped GST PRAM cells have higher dynamic resistance with small sized bottom electrode contact and lower RESET voltage (about 1.2 V, 50 ns) than un-doped GST PRAM cells (about 1.6 V, 50 ns). The resistance switching ratio (RRESET to RSET) was about 100. The results of this study indicate that nitrogen doping into GST film and smaller size of bottom electrode contact reduce RESET power for PRAM operation.

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