共查询到20条相似文献,搜索用时 15 毫秒
1.
Dielectric-breakdown-like forming process in the unipolar resistance switching of Ta2O5−x thin films
Moon Jee YoonShin Buhm Lee Hyang Keun YooSoobin Sinn Bo Soo Kang 《Current Applied Physics》2012,12(3):846-848
We report unipolar resistance switching (URS) in Ta2O5−x thin films. The current increased suddenly when we applied voltages up to 5-7 V to the pristine state of Pt/Ta2O5−x/Pt, Ni/Ta2O5−x/Pt, and Ti/Ta2O5−x/Pt cells. Just after this forming process, we observed a repetitive URS occurring independently of the electrodes. We found that the required voltages for the forming process did not depend on the top electrode type, but on the film thickness. These results suggest that the forming process is driven by a dielectric-breakdown-like phenomenon, and that URS occurs due to the formation and rupture of conducting channels inside the Ta2O5−x thin film. 相似文献
2.
The Ti-doped Ta2O5 thin films (<10 nm) obtained by rf sputtering are studied with respect to their composition, dielectric and electrical properties. The incorporation of Ti is performed by two methods - a surface doping, where a thin Ti layer is deposited on the top of Ta2O5 and a bulk doping where the Ti layer is sandwiched between two layers of Ta2O5. The effect of the process parameters (the method and level of doping) on the elemental distribution in-depth of the films is investigated by the time of flight secondary ion mass spectroscopy (ToF-SIMS). The Ti and Ta2O5 are intermixed throughout the whole thickness but the layers are very inhomogeneous. Two sub-layers exist in all the samples — a near interfacial region which is a mixture of Ta-, Ti-, Si-oxides as well as TaSiO, and an upper Ti-doped Ta2O5 sub-layer. For both methods of doping, Ti tends to pile-up at the Si interface. The electrical characterisation is performed on capacitors with Al- and Ru-gate electrodes. The two types of MIS structures exhibit distinctly different electrical behavior: the Ru gate provides higher dielectric permittivity while the stacks with Al electrode are better in terms of leakage currents. The specific metal-dielectric reactions and metal-induced electrically active defects for each metal electrode/high-k dielectric stack define its particular electrical behavior. It is demonstrated that the Ti doping of Ta2O5 is a way of remarkable improvement of leakage characteristics (the current reduction with more than four orders of magnitude as compared with undoped Ta2O5) of Ru-gated capacitors which originates from Ti induced suppression of the oxygen vacancy related defects. 相似文献
3.
《Current Applied Physics》2019,19(11):1286-1295
We report the coexistence of resistive switching and magnetism modulation in the Pt/Co3O4/Pt devices, where the effects of thermal annealing and film thickness on the resistive and magnetization switching were investigated. The sol-gel derived nanocrystalline Co3O4 thin films obtained crack-free surface and crystallized cubic spinel structure. The 110 nm Co3O4 film based device annealed at 600 °C exhibited optimum resistive switching parameters. From I–V curves fitting and temperature dependent resistance, the conduction mechanism in the high-voltage region of high resistance state was dominated by Schottky emission. Magnetization-magnetic field loops demonstrated the ferromagnetic behaviors of the Co3O4 thin films. Multilevel saturation magnetization of the Co3O4 thin films can be easily realized by tuning the resistance states. Physical resistive switching mechanism can be attributed to the rejuvenation and annihilation of conductive filament consisting of oxygen vacancies. Results suggest that Pt/Co3O4/Pt device shows promising applications in the multifunctional electromagnetic integrated devices. 相似文献
4.
《Current Applied Physics》2019,19(9):987-991
Orthorhombic Bi2SiO5 thin films with dense surface were synthesized by using a chemical solution deposition method. The crystallized films were first utilized to implement resistive memory cells with Pt/Bi2SiO5/Pt sandwich architecture. It exhibited outstanding switching parameters including concentrated distributions of low and high resistance states, uniform switching voltages, cycling endurance, and long retention. Furthermore, the model of formation and rupture of conductive filaments consisted of oxygen vacancies was used to well explain resistive switching behavior. The results revealed that the solution-processed Bi2SiO5 thin film devices have great potential for forefront application in nonvolatile memory. 相似文献
5.
6.
B. C. Luo J. Wang X. S. Cao K. X. Jin C. L. Chen 《Applied Physics A: Materials Science & Processing》2013,113(3):779-785
Multiferroic and resistive switching properties of single-phase polycrystalline perovskite BiFe0.95Cr0.05O3 (BFCO) thin films grown on Pt/Ti/SiO2/Si substrates by radio-frequency magnetron sputtering were investigated. The BFCO film shows ferroelectric and magnetic properties simultaneously at room temperature, and also exhibits a good piezoelectric property with remanent effective piezoelectric coefficient d 33,f ~55±4 pm/V. An obviously resistive switching behavior was observed in the BFCO thin film at room temperature, which was discussed by the filamentary conduction mechanism associated with the redistribution of oxygen vacancies. 相似文献
7.
We investigated the characteristics and the mechanism of Pt/La2O3/Pt resistance switching memory with a set of measurements. The La2O3 films were determined as nano‐poly‐crystalline (diameter of the nanocrystals 5–10 nm) by XRD and HRTEM analysis. The Pt/La2O3/Pt device exhibited excellent resistive switching properties, including low switching voltage (<2 V), large low/high resistance ratio (>108), and good cycling endurance property. The conduction mecha‐ nisms of the Pt/La2O3/Pt device were revealed with current–voltage characteristics, which are different in the low and high resistance states. Furthermore, XPS analysis and temperature‐dependent resistance measurement in the low resistance state showed that the conducting filaments in the Pt/La2O3/Pt device are mainly affected by oxygen defects rather than metallic La. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
8.
Xinman Chen Guangheng Wu Hailei Zhang Ni Qin Tao Wang Feifei Wang Wangzhou Shi Dinghua Bao 《Applied Physics A: Materials Science & Processing》2010,100(4):987-990
We report on reversible bipolar resistance switching effects in multiferroic BiFeO3 thin films without electroforming. The BiFeO3 thin films with (110) preferential orientation were prepared on LaNiO3-electrodized Si substrates with a Pt/BiFeO3/LaNiO3 device configuration. The resistance ratio of high resistance state (HRS) to low resistance state (LRS) of the devices was
as high as three orders of magnitude. The dominant conduction mechanisms of LRS and HRS were dominated by ohmic behavior and
trap-controlled space charge limited current, respectively. The resistance switching mechanism of the devices was discussed
using a modified Schottky-like barrier model taking into account the movement of oxygen vacancies. 相似文献
9.
Amorphous TaOx thin films were deposited at different temperatures, and the resistance switching properties of the Pt/TaOx/Pt structure were investigated. X‐ray photoelectron spectroscopy showed that the amount of Ta2O5 in the film decreased and the content of Ta suboxides increased substantially when the growth temperature was increased. Unipolar resistance switching near the anode was stable only for TaOx film grown at room temperature. The experimental results revealed the critical effect of the film composition on the resistance switching behavior of TaOx films. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
10.
Effects of O2/Ar ratio and annealing temperature on electrical properties of Ta2O5 film prepared by magnetron sputtering 下载免费PDF全文
The effects of the oxygen-argon ratio on electric properties of Ta2O5 film prepared by radio-frequency magnetron sputtering were investigated.The Ta2O5 partially transforms from the amorphous phase into the crystal phase when annealing temperatures are 800℃ or higher.The lattice constant of Ta2O5 decreases with the increase of the O2/Ar ratio,which indicates that oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies during the deposition process.For the films deposited in working gas mixtures with different O2/Ar ratios and subsequently annealed at 700℃,the effective dielectric constant is increased from 14.7 to 18.4 with the increase of the O2/Ar ratio from 0 to 1.Considering the presence of an SiO2 layer between the film and the silicon substrate,the optimal dielectric constant of Ta2O5 film was estimated to be 31.Oxygen gas in the working gas mixture contributes to reducing the density of oxygen vacancies,and the oxygen vacancy density and leakage current of Ta2O5 film both decrease with the increase of the O2/Ar ratio.The leakage current decreases after annealing treatment and it is minimized at 700℃.However,when the annealing temperature is 800℃ or higher,it increases slightly,which results from the partially crystallized Ta2O5 layer containing defects such as grain boundaries and vacancies. 相似文献
11.
Thickness‐dependent electroforming behavior of ultra‐thin Ta2O5 resistance switching layer 下载免费PDF全文
Tae Hyung Park Seul Ji Song Hae Jin Kim Soo Gil Kim Suock Chung Beom Yong Kim Kee Jeung Lee Kyung Min Kim Byung Joon Choi Cheol Seong Hwang 《固体物理学:研究快报》2015,9(6):362-365
Electroforming behaviours of Ta2O5 resistance switching memory cell with a diameter of 28 nm and different thickness (0.5–2.0 nm) of Ta2O5 layer have been examined. The devices showed a constant forming electric field of 0.54 V/nm regardless of Ta2O5 thickness. The electroforming with negative bias to top TiN electrode was ascribed to electric field‐ driven migration of oxygen vacancies, originally residing near the bottom interface, toward the top electrode interface and formation of conducting filaments. The estimated electroforming energy (0.094–0.14 eV) was favourably compared with the hopping energy of electrons from the VO site to a nearby Ta site. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
12.
X. Cao X. M. Li X. D. Gao Y. W. Zhang X. J. Liu Q. Wang L. D. Chen 《Applied Physics A: Materials Science & Processing》2009,97(4):883-887
Nanocrystalline TiO2 thin films were fabricated on Pt(111)/Ti/SiO2/Si substrates by the thermal oxidation of evaporated Ti films. Effects of the compliance current on the resistive switching
behavior of the Pt/TiO2/Pt sandwich structures were studied in detail. The reset current increased when the compliance current increased from 10 mA
to 20 mA. When the compliance current exceeded 20 mA, the switching behavior disappeared, which could be attributed to the
change of the conducting behavior in the low-resistance state. A resistance change ratio of as high as 102 was obtained between the high-resistance state and the low-resistance state. The study of the effect of compliance current
contributes to obtaining stable and reliable resistive switching behavior for nonvolatile memory applications. 相似文献
13.
Microstructures and impedance characteristics of chemical-solution-derived Bi3.15Nd0.85Ti3O12 thin films were studied as functions of temperature. A dielectric anomaly was found at around 450°C, corresponding to the
paraelectric to ferroelectric transition. Via complex impedance studies, grain and grain boundary contributions to the impedance
were separated. The resistance of grain and grain boundaries is found governed by the same kind of space charge with an activation
energy around 1.1 eV, close to that of oxygen vacancies in perovskite ferroelectrics. The low temperature ac conductance of
BNdT thin films shows a frequency dispersion, which can also be ascribed to space charges mainly due to oxygen vacancies.
The results were compared with SrBi2Ta2O9 in terms of oxygen vacancy conductivity. 相似文献
14.
为了研究阻变存储器导电细丝的形成位置和分布规律, 使用X射线光电子能谱研究了Ti/HfO2/Pt阻变存储器件单元中Hf 4f的空间分布, 得到了阻变层的微结构信息. 通过I-V测试, 得到该器件单元具有典型的阻变特性; 通过针对Hf 4f的不同深度测试, 发现处于低阻态时, 随着深度的增加, Hf4+化学组分单调地减小; 而处于高阻态和未施加电压前, 该组分呈现波动分布; 通过Hf4+在高阻态和低阻态下组分含量以及电子能损失谱分析, 得到高阻态下Hf4+组分的平均含量要高于低阻态; 另外, 高阻态和低阻态下的O 1s谱随深度的演变也验证了Hf4+的变化规律. 根据实验结果, 提出了局域分布的氧空位聚簇可能是造成这一现象的原因. 空位簇间的链接和断裂决定了导电细丝的形成和消失. 由于导电细丝容易在氧空位缺陷聚簇的地方首先形成, 这一研究为导电细丝的发生位置提供了参考. 相似文献
15.
Yun Hoe Kim Jong-Han SongJin Sang Kim Seok-Jin YoonKyung Bong Park Ji-Won Choi 《Applied Surface Science》2011,258(2):843-847
The dielectric properties of MgO-Ta2O5 continuous composition spread (CCS) thin films were investigated. The MgO-Ta2O5 CCS thin films were deposited on Pt/Ti/SiO2/Si substrates by off-Axis RF magnetron sputtering system, and then the films were annealed at 350 °C with rapid thermal annealing system in vacuum. The dielectric constant and loss of MgO-Ta2O5 CCS thin films were plotted via 1500 micron-step measuring. The specific point of Ta2O5-MgO CCS thin film (post annealed at 350 °C) showing superior dielectric properties of high dielectric constant (k ∼ 28) and low dielectric loss (tan δ < 0⋅004) at 1 MHz were found in the area of 3-5 mm apart from Ta2O5 side on the substrate. The cation's composition of thin film was Mg:Ta = 0.4:2 at%. 相似文献
16.
Li Lu Takashi Nishida Masahiro Echizen Yasuaki Ishikawa Kiyoshi Uchiyama Yukiharu Uraoka 《Applied Physics A: Materials Science & Processing》2013,112(2):425-430
Sol–gel-derived SrTa2O6 thin films were fabricated at a low temperature of 500 °C. To improve their leakage current properties, additional UV/O3-assisted annealing was performed from room temperature to 290 °C. UV/O3 treatment at 290 °C gave a very low leakage current that was six orders of magnitude lower than that of an untreated thin film. During UV/O3-assisted annealing, Si and Ti ions diffused from the substrates into the SrTa2O6 thin films and occupied the Ta5+ sites, subsequently generating Si? and Ti?. At a heating temperature of 290 °C, large amounts of Ti ions diffused throughout the SrTa2O6 thin film. These Ti ions contributed to the generation of inactive combinations of $(\mathrm{Si}^{-}\mbox{--}\mathrm{V}_{\mathrm{o}}^{+})^{+}\mbox{--}\mathrm{Ti}^{-}$ and $(\mathrm{Ti}^{-}\mbox{--}\mathrm{V}_{\mathrm{o}}^{+})^{+}\mbox{--}\mathrm{Ti}^{-}$ , which greatly reduced oxygen vacancies (Vo). Thus, the leakage current was significantly reduced. 相似文献
17.
Lead free Ba0.92Ca0.08Ti0.95Zr0.05O3 (BCZT) thin films were deposited on Pt/Ti/SiO2/Si and LaNiO3(LNO)/Pt/Ti/SiO2/Si substrates by a sol–gel processing technique, respectively. The effects of substrate on structure, dielectric and piezoelectric properties were investigated in detail. The BCZT thin films deposited on LNO/Pt/Ti/SiO2/Si substrates exhibit (100) orientation, larger grain size and higher dielectric tunability (64%). The BCZT thin films deposited on Pt/Ti/SiO2/Si exhibit (110) orientation, higher Curie temperature (75 °C), better piezoelectric property (d33 of 50 pm/V) and lower dielectric loss (0.02). The differences in dielectric and piezoelectric properties in the two kinds of oriented BCZT films should be attributed to the difference of structure, in-plane stress and polarization rotation in orientation engineered BCZT films. 相似文献
18.
《Current Applied Physics》2014,14(4):538-542
Amorphous Pr0.7Ca0.3MnO3 (APCMO) films were grown on a Pt/Ti/SiO2/Si (Pt–Si) substrate at temperatures below 500 °C and the Pt/APCMO/Pt–Si device showed unipolar resistive switching behavior. Conduction behavior of the low resistance state (LRS) of the Pt/APCMO/Pt–Si device followed Ohm's law, and the resistance in LRS was independent of the size of the device, indicating that the conduction behavior in LRS can be explained by the presence of the conductive filaments. On the other hand, the resistance in the high resistance state (HRS) decreased with increasing the device size, and the conduction mechanism in the HRS was explained by Schottky emission. 相似文献
19.
Dong-Xu Zhang Yu-Xiang Zheng Qing-Yuan Cai Wei Lin Kang-Ning Wu Peng-Hui Mao Rong-Jun Zhang Hai-bin Zhao Liang-Yao Chen 《Applied Physics A: Materials Science & Processing》2012,108(4):975-979
An effective method for determining the optical constants of Ta2O5 thin films deposited on crystal silicon (c-Si) using spectroscopic ellipsometry (SE) measurement with a two-film model (ambient–oxide–interlayer–substrate) was presented. Ta2O5 thin films with thickness range of 1–400 nm have been prepared by the electron beam evaporation (EBE) method. We find that the refractive indices of Ta2O5 ultrathin films less than 40 nm drop with the decreasing thickness, while the other ones are close to those of bulk Ta2O5. This phenomenon was due to the existence of an interfacial oxide region and the surface roughness of the film, which was confirmed by the measurement of atomic force microscopy (AFM). Optical properties of ultrathin film varying with the thickness are useful for the design and manufacture of nano-scaled thin-film devices. 相似文献
20.
Fengzhen Huang Xiaomei Lu Zhe Wang Weiwei Lin Yi Kan Huifeng Bo Wei Cai Jinsong Zhu 《Applied Physics A: Materials Science & Processing》2009,97(3):699-704
Multiferroic BiFeO3/Bi3.25La0.75Ti3O12 films annealed in different atmospheres (N2 or O2) were prepared on Pt/Ti/SiO2/Si substrates via a metal organic decomposition method. Based on our experimental results, it is considered that, in the
films annealed in N2, fewer Fe2+ ions while more oxygen vacancies are involved. As a result, at room temperature, predominated by the reduced Fe2+ fraction, lower leakage current and dielectric loss, better ferroelectric property while reduced magnetization are observed.
However, the oxygen vacancies might be thermally activated at elevated temperature; thus, more strongly temperature-dependent
leakage current and a higher dielectric relaxation peak are observed for the films annealed in N2. 相似文献