第 13 屆台灣靜電放電防護技術暨可靠度技術研討會 2014 taiwan esd and reliability...

第 13屆台灣靜電放電防護技術暨可靠度技術研討會 2014 Taiwan ESD and Reliability Conference

Resistive switching and device Resistive switching and device reliability in ZnO-based reliability in ZnO-based

nonvolatile memory devicesnonvolatile memory devices

Ming Chuan UniversityDepartment of Electronic Engineering

Wen-Ping Chiang, Min-Yu Yang, Chin Wang, Ge-Jia Liao, Hsien-Mei Wang, and Fu-Chien Chiu*

2第 13屆台灣靜電放電防護技術暨可靠度技術研討會 2014 Taiwan ESD and Reliability Conference

OutlineOutline

Introduction Experiment Results and discussion Conclusions References


Overview of memoriesOverview of memories


IntroductionIntroduction Because traditional Flash memory device are approaching

physical limitations, the developments of next generation nonvolatile memory devices are in urgent need.

Resistive random access memory (RRAM) has attracted a great deal of attention.

Why? Structural simplicity Low operation voltage Excellent durability Area miniaturization CMOS process compatibility High speed Multibit function


Classification of RRAMClassification of RRAM

RRAM materials:

Perovskite-type oxides

Binary metal oxides

Solid-state electrolytes

Organic compounds

Amorphous Si


ExperimentsExperiments In this work, Pt/ZnO/Pt MIM diodes were fabricated.

Si

SiO2

Ti

Pt

ZnO(25nm)

Pt Pt

V Topelectrode Bottom

electrode

Pt

Device fabrication process:

Substrate wafers (Pt/Ti/SiO2/Si)

ZnO (25 nm) deposition

(RF magnetron sputtering)

Shadow mask

Pt top electrode deposition

(RF magnetron sputtering)

Device formation

(Pt / ZnO (25 nm) / Pt)


Results and discussionResults and discussion

Physical analysis of thin filmPhysical analysis of thin film

Electrical characteristicsElectrical characteristics

Resistive switching behaviorResistive switching behavior

Pulse width effect on VPulse width effect on VSETSET/V/VRESETRESET

Temperature effect on VTemperature effect on VSETSET/V/VRESETRESET

Conduction mechanism in ZnOConduction mechanism in ZnO

Endurance and memory windowEndurance and memory window


XPS in Pt/ZnO/PtXPS in Pt/ZnO/Pt

X-ray photoelectron spectroscopy (XPS) spectrum of O 1s in ZnO film.The peaks at 530 and 532 eV are due to lattice oxygen (ZnO) and nonlattice oxygen (oxygen vacancy).


XPS in Pt/ZnO/Pt XPS in Pt/ZnO/Pt

XPS spectrum of Zn 2p in ZnO film. Zn 2p1/2 and 2p3/2 for Zn2+ correspond to the peaks at 1046.2 and 1023.2 eV. Zn 2p1/2 and 2p3/2 for Zn0 correspond to the peaks at 1047 and 1024 eV.


Resistive switching characterizationResistive switching characterization

In Pt/ZnO/Pt structure, bipolar resistive switching behavior was found and electroforming was required.


Switching voltage vs. ac voltage pulse widthSwitching voltage vs. ac voltage pulse width

Both set voltage (VSET) and reset voltage (VRESET) are increased with decreasing ac voltage pulse width.


Switching voltage vs. temperatureSwitching voltage vs. temperature

Temperature dependence on set/reset voltage.


I-V characteristics in HRSI-V characteristics in HRS

Temperature-dependent I-V characteristics in high-resistance state (HRS).


Hopping conduction in HRSHopping conduction in HRS

Trap spacing (a) extraction of hopping conduction in high-resistance state (HRS).


Arrhenius plotArrhenius plot

Arrhenius plot for trap level (Φ t) extraction.


J-E curves in LRSJ-E curves in LRS

Temperature-dependent J-E curves in low-resistance state (LRS).


DC Cycling EnduranceDC Cycling Endurance

Voltage-swept I-V characteristics of dc cycling endurance.


Weibull plots in HRS and LRSWeibull plots in HRS and LRS

Weibull plots of HRS/LRS resistances during dc switching cycles.


AC/DC memory windowAC/DC memory window

Memory window as a function of the number of dc/ac switching.


ConclusionConclusion1. The bipolar resistive switching behavior was found in Pt/ZnO/Pt

structure.

2. The amplitude of resistive switching voltage is dependent on the

applied ac voltage pulse width (Wac).

3. During the set process, the conductive filaments formed are

associated with the defect state of interstitial zinc in ZnO film. The

defect trap spacing is about 2 nm and the trap energy level is about

0.46 eV.

4. For the test of dc cycling endurance, a serious memory window

closure is considered. Whereas, the ac cycling endurance can be over

106 switching cycles.


ReferencesReferences[1] W. W. Zhuang et al., “Novell colossal magnetoresistive thin film nonvolatile resistance random

access memory (RRAM),” in IEDM Tech. Dig., 2002, pp. 193-196.

[2] H. Akinaga and H. Shima, “Resistive random access memory (ReRAM) based on metal oxides,” Proc. IEEE, vol. 98, no. 12, pp. 2237-2251, Dec. 2010.

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ReferencesReferences[10] M. Villafuerte, S.P. Heluani, G. Juárez, G. Simonelli, G. Braunstein, and S. Duhalde, “Electric-pulse-induced

reversible resistance in doped zinc oxide thin films,” Appl. Phys. Lett., vol. 90, no. 5, p. 052105, Jan. 2007.

[11] W.Y. Chang, Y.C. Lai, T.B. Wu, S.F. Wang, F. Chen, and M.J. Tsai, “Unipolar resistive switching characteristics of ZnO thin films for nonvolatile memory applications,” Appl. Phys. Lett., vol. 92, no. 2, p. 022110, Jan. 2008.

[12] N. Xu, L. Liu, X. Sun, X. Liu, D. Han, Y. Wang, R. Han, J. Kang, and B. Yu, “Characteristics and mechanism of conduction/set process in TiN/ZnO/Pt resistance switching random-access memories,” Appl. Phys. Lett., vol. 92, no. 23, p. 232112, Jun. 2008.

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[17] D. Ielmini, F. Nardi, and C. Cagli, “Universal reset characteristics of unipolar and bipolar metal-oxide RRAM,” IEEE Trans. Electron Devices, vol. 58, no. 10, pp. 3246-3253, Oct. 2011.

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第 13屆台灣靜電放電防護技術暨可靠度技術研討會 2014 Taiwan ESD and Reliability Conference

Thank you for your attention.Thank you for your attention.

第 13 屆台灣靜電放電防護技術暨可靠度技術研討會 2014 taiwan esd and reliability...

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