Browsing by Author "Kumar, Dayanand"

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Conductive bridge random access memory characteristics of SiCN based transparent device due to indium diffusion
(2018-03-23)
Kumar, Dayanand
;
Aluguri, Rakesh
;
Chand, Umesh
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
In this work, the transparent bipolar resistive switching characteristics of a SiCN-based ITO/ SiCN/AZO structure due to In diffusion from ITO is studied. The SiCN based device is found to be 80% transparent in the visible wavelength region. This device, with AZO as both top and bottom electrodes, does not show any RRAM property due to deposition of the high quality O-2-free SiCN film. Replacing the AZO top electrode with ITO in this device results in good resistive switching (RS) characteristics with a high on/off ratio and long retention. Replacing the SiCN film with ZrO2 also results in excellent RS characteristics due to the formation of an oxygen vacancies filament inside the ZrO2 film. A resistance ratio of on/off is found to be higher in the SiCN based device compared to that of the ZrO2 device. Diffusion of In from ITO into the SiCN film on application of high positive voltage during forming can be attributed to the occurrence of RS in the device, which is confirmed by the analyses of energy dispersive spectroscopy and secondary-ion mass spectrometry. This study shows a pathway for the fabrication of CBRAM based transparent devices for non-volatile memory application.
Enhancement of resistive switching properties in nitride based CBRAM device by inserting an Al2O3 thin layer
(2017-05-15)
Kumar, Dayanand
;
Aluguri, Rakesh
;
Chand, Umesh
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
In this letter, we propose a method to enhance resistive switching properties in SiCN-based conductive-bridge resistive switching memory (CBRAM) devices by inserting a thin Al2O3 layer between the SiCN resistive switching layer and the TiN bottom electrode. Compared with the Cu/Ta/SiCN/TiN single-layer device, the Cu/Ta/SiCN/Al2O3/TiN double layer device exhibits uniform resistive switching, long stable endurance cycles (>1.6 x 10(4)), and stable retention (10(4)s) at 125 degrees C. These substantial improvements in the resistive switching properties are attributed to the location of the formation and rupture of conductive filaments that can be precisely controlled in the device after introducing the Al2O3 layer. Moreover, a multilevel resistive switching characteristic is observed in the Cu/Ta/SiCN/Al2O3/TiN double layer CBRAM device. The distinct six-level resistance states are obtained in double layer devices by varying the compliance current. The highly stable retention characteristics (>10(4)) of the Cu/Ta/SiCN/Al2O3/TiN double layer device with multilevel resistance states are also demonstrated. Published by AIP Publishing.
High Performance Bipolar Resistive Switching Characteristics in SiO2/ZrO2/SiO2 Tri-layer Based CBRAM Device
(2017-01-01)
Kumar, Dayanand
;
Aluguri, Rakesh
;
Chand, Umesh
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
The bipolar resistive switching properties of the CBRAM device are investigated for nonvolatile memory applications in a SiO2/ZrO2/SiO2 structure. The device shows good switching characteristics with set/reset voltages less than +1 V/-1 V with a variation of less than 0.2 V. The SiO2/ZrO2/SiO2 tri-layer CBRAM device exhibits excellent memory performances, such as stable DC endurance up to 10(3) cycles during the test without degradation, good retention ability (>10(4) s) at a temperature of 100 degrees C with more than 10(2) on/off resistance ratio.
High-Performance TiN/Al2O3/ZnO/Al2O3/TiN Flexible RRAM Device With High Bending Condition
(2020-02-01)
Kumar, Dayanand
;
Chand, Umesh
;
Siang, Lew Wen
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
The bipolar resistive switching (RS) characteristics of the ZnO-based TiN/Al2O3/ZnO/Al2O3/TiN structure are investigated for flexible nonvolatile memory applications. Using a thin Al2O3 buffer layer on both sides of the ZnO device shows uniform and eminently stable bipolar resistance switching characteristics. The device exhibits good RS with more than two orders of resistance ON-OFF ratio, retention of 10(4) s at 120 C, good dc endurance 10(4) cycles, and high ac endurance of 10(8) cycles with 40-ns pulsewidth without any degradation. The device shows high mechanical stability when under 10(4) continuous repetitive flexible bendings, indicating that high endurance with a very small bending radius of up to 3 mm. The lower Gibbs free energy of the Al2O3 (-1676 kJ/mol) film compared with the ZnO (-320.4 kJ/mol) and TiO2 (-994 kJ/mol) films can improve the RS properties of the TiN/Al2O3/ZnO/Al2O3/TiN device. The significant improvement in the TiN/Al2O3/ZnO/Al2O3/TiN device is due to the reason that thin Al2O3 layers on both sides of ZnO would help stabilize the local oxygen migrations for the formation and rupture of the conductive filament during the continuous switching cycles, resulting in high memory switching characteristics.
Metal induced crystallized poly-Si-based conductive bridge resistive switching memory device with one transistor and one resistor architecture
(2015-11-16)
Chand, Umesh
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Huang, Chun-Yang
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Kumar, Dayanand
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
In this letter, the metal induced crystallization (MIC) process is used in the Si-based conductive bridging resistive random access memory (CBRAM) application. The amorphous Si (a-Si) is transformed to crystallized poly-silicon (poly-Si) at a low temperature by using Ni metal for inducing poly-Si to provide the resistive switching. The MIC process can produce a highly preferred orientation poly-Si film, which can create the exact paths or grain boundaries through the top and down electrodes in the present CBRAM device. The grain boundary in MIC poly-Si layer can confine the conductive filament of metal bridging growth in it, which can improve the switching fluctuation behavior in the nonvolatile memory application. Compared with the a-Si based device, a significant improvement in terms of resistive switching parameters such as stability and resistance distribution is demonstrated in the MIC poly-Si CBRAM device. Moreover, the well-behaved memory performance, such as high ON/OFF resistance ratio (4 order), a large AC endurance (10(6)), and good retention characteristics (10(4) s at 125 degrees C) are achieved in the Cu/poly-Si/n(+)-Si CMOS compatible cross bar structure. (c) 2015 AIP Publishing LLC.
One Bipolar Selector-One Resistor for Flexible Crossbar Memory Applications
(2019-03-01)
Kumar, Dayanand
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Aluguri, Rakesh
;
Chand, Umesh
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
A bipolar, highly nonlinear n-p-n selector is coupled in series with resistive switching memory device to suppress the sneak path current. The memory characteristics are measured for the crossbar array fabricated on a flexible polyethylene terephthalate substrate. Dominant conduction mechanism is the Zener tunneling to obtain the high nonlinearity in the selector device. This phenomenon validates the I-V characteristics which are temperature dependent, which leads to decrease in the turn-on voltage of the device as the temperature increases. The proposed one bipolar selector-one resistor device demonstrates better memory characteristics with the high nonlinearity (similar to 10(3)), observable memory window of about one order, excellent ac endurance (10(7)) cycles, fast switching speed (60 ns), and stable retention (10(4) s) at 100 degrees C. The results show the substantial potential of the proposedone selector-one-resistor structure in suppressing the leakage current, making it attractive for future high-density flexible crossbar memory array.
Role of Al2O3 thin layer on improving the resistive switching properties of Ta5Si3-based conductive bridge random accesses memory device
(2018-04-01)
Kumar, Dayanand
;
Aluguri, Rakesh
;
Chand, Umesh
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
Ta5Si3-based conductive bridge random access memory (CBRAM) devices have been investigated to improve their resistive switching characteristics for their application in future nonvolatile memory technology. Changes in the switching characteristics by the addition of a thin Al2O3 layer of different thicknesses at the bottom electrode interface of a Ta5Si3-based CBRAM devices have been studied. The double-layer device with a 1 nm Al2O3 layer has shown improved resistive switching characteristics over the single layer one with a high on/off resistance ratio of 10(2), high endurance of more than 10(4) cycles, and good retention for more than 10(5) s at the temperature of 130 degrees C. The higher thermal conductivity of Al2O3 over Ta5Si3 has been attributed to the enhanced switching properties of the double-layer devices. (C) 2018 The Japan Society of Applied Physics.
ZrN-Based Flexible Resistive Switching Memory
(2020-05-01)
Kumar, Dayanand
;
Chand, Umesh
;
Siang, Lew Wen
;
Tseng, Tseung-Yuen
;
電子工程學系及電子研究所
In this letter, ZrN-based resistive random access memory (RRAM) is investigated for flexible memory applications for the near future. Due to the room-temperature fabrication process, the device is suitable for low-temperature flexible monolithic technologies. The TiN/ZrN/TiN device exhibits excellent AC endurance cycling (10(7)), a rapid speed (45 ns) and stable retention (10(4) s) at 100 degrees C without any degradation. In addition, RRAM devices built with an additional HfN interface layer exhibit small operational voltage variations and stable switching characteristics. The flexibility of the device is excellent, and it maintains excellent electrical characteristics at a bending radius of up to 4 mm.