Tuning the stoichiometry and electrical properties of tantalum oxide thin films

Li, Yang; Sanna, Simone; Norrman, Kion; Christensen, Dennis Valbjørn; Pedersen, Christian Søndergaard; Lastra, Juan Maria García; Traulsen, Marie Lund; Esposito, Vincenzo; Pryds, Nini

doi:10.1016/j.apsusc.2018.11.153

Cited by 23 publications

(16 citation statements)

References 38 publications

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“…This corresponds to the so-called "plateau" region wherein ρ is approximately linear with O content, which has previously been observed for TaO x films made by the "triode" sputtering technique [13,14]. The dependence becomes strong, close-to-exponential in the second region of O content within ∼50-70 at.%, consistent with previous reports [13,28,29]. The third region is for O content of 70 at.%, when the film composition approaches that of stoichiometric Ta 2 O 5 and ρ experiences a rapid increase, where most films with O content above ∼70 at.% had ρ values that were too high to be measured with our (direct-current) setup.…”

Section: Resultssupporting

confidence: 89%

Tantalum Suboxide Films with Tunable Composition and Electrical Resistivity Deposited by Reactive Magnetron Sputtering

et al. 2022

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Tantalum-based films with tailored composition, density, and electrical resistivity are of interest for next generation hohlraums for magnetized indirect-drive inertial confinement fusion. Here, we use reactive direct-current magnetron sputtering to deposit tantalum suboxide films with O content in the range of 46–71 at.%. In contrast to a common approach involving varying reactive gas contents, compositional control is achieved kinetically by changing the total chamber pressure and the deposition rate, while keeping the working gas mix of Ar-5%O2 constant. The resultant films are X-ray amorphous with electrical resistivity varying by over seven orders of magnitude. The dominant conduction mechanism changes from metallic to activated tunneling above ∼55 at.% of O, which is characterized by a sharp increase in resistivity and a decrease in the carrier density at low temperatures.

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Section: Resultssupporting

confidence: 89%

Tantalum Suboxide Films with Tunable Composition and Electrical Resistivity Deposited by Reactive Magnetron Sputtering

et al. 2022

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“…32 This allows to tailor and control the properties resulting from oxygen vacancies in a dynamic manner via electric fields, temperature, pressure, or light by forming/healing defects or by moving and redistributing defects within the device. 3,29,[33][34][35][36][37][38][39][40][41][42][43] This area, currently known as defect engineering, is aimed at manipulating the nature and the concentration of defects in a material to tune its properties in a desired manner or to generate completely new and unexpected properties. 16,17 The formation and annihilation of oxygen vacancies in transition metal oxides involves the dynamics of ionic defects, the exchange of oxygen from or into the surrounding, and the transfer of electronic charges from or into the material, rendering oxygen vacancy formation a complex solid-state redox-process.…”

mentioning

confidence: 99%

Oxygen vacancies: The (in)visible friend of oxide electronics

Gunkel

Christensen

Chen

et al. 2020

Applied Physics Letters

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271

151

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Oxygen vacancies play crucial roles in determining the physical properties of metal oxides, representing important building blocks in many scientific and technological fields due to their unique chemical, physical, and electronic properties. However, oxygen vacancies are often invisible because of their dilute concentrations. Therefore, characterizing and quantifying their presence is of utmost importance for understanding and realizing functional metal oxide devices. This, however, is oftentimes a non-trivial task. In this Perspective paper, we discuss the relevant regimes of concentrations and associated phenomena arising from oxygen vacancies. We then focus on experimental techniques available for observing oxygen vacancies at widely different levels of concentrations. Finally, we discuss current challenges and opportunities for utilizing oxygen vacancies in metal oxides.

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“…is the step function. The authors in [37][38][39] customised the parameters of a memristor by adjusting the process recipe such as manipulating the thin-film growth conditions, variation of annealing time after deposition, variation of partial pressure of oxygen gas, etc. A memristor with multilevel stable resistance states from 1 to 200 kΩ has been reported in [37].…”

Section: Memristormentioning

confidence: 99%

Memristor‐transistor hybrid ternary content addressable memory using ternary memristive memory cell

Khan

Rashid

2021

IET Circuits, Devices & Systems

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A memristor-transistor hybrid ternary content addressable memory (MTCAM) with a memristor-based ternary memory cell is proposed. New emerging devices like memristors have recently been explored to overcome the limitations of CMOS-based memory circuits. The memristor is used as a binary memory cell in these MTCAM designs to replace a CMOS-based memory cell. This proposed design used a memristor as a ternary memory cell by exploiting its variable resistance characteristics. The associated wiring is reduced almost by a factor of 2 as a ternary cell is used instead of two binary cells. Area efficiency is further enhanced as the MTCAM cell is comprised of two transistors and two memristors (2T2M). A segmentation technique of match line along with a robust write/ search operation method is presented to enhance the search speed of the proposed MTCAM. Simulation based on a mathematical model of memristor is presented and analysed using 65 nm TSMC MOS model parameters. Corner simulations and Monte Carlo simulations are carried out to substantiate the robustness of the design against process variation. Simulation results show the worst search delay of 0.75 ns and the energy/bit/search of 0.866 fJ for the 128 � 128 bit MTCAM. 1 | INTRODUCTION Large data computation requires massive parallel processing with heavy memory access traffic [1,2]. Content addressable memory (CAM), a widely used hardware search engine for high-speed parallel data search applications [3], provides the capability to search data across an entire memory and returns the address in a single clock cycle [4,5]. Ternary content addressable memory (TCAM) adds more flexibility in the search operation by providing a third state called Mask ('don't care') state. The 'X' state provides a groupsearch option, that is, searching a portion of the word when necessary instead of searching the whole word. This additional 'X' state makes TCAM more powerful in searching by returning match condition regardless of the input search data [6]. TCAM, with its high throughput, is a promising solution for systems that deal with large data, such as a high-speed search engine, data base engine, data mining and multimedia processing [7-9]. CAM density has improved significantly over the past two decades with aggressive CMOS technology scaling [10]. Aggressive scaling of CMOS technology steadily increases the power density of the chip causing a heating problem [11,12]. TCAM needs 2-bit memory to accommodate the third state, 'X'. Multiple (12-16) transistors are thus needed to form TCAM cells, which require large area and, eventually, high power consumption [4]. This area and power constraint limits the usage of CMOS-based TCAM in network and classification applications [13,14]. New emerging devices such as magnetotunnelling junction-based devices [15], metamaterials-based optical nano circuits [16], carbon nanotube field effect transistors [17] and memristors [18,19] are being explored to find solutions for these area and power limitations of their CMOS counterpart. Memristor, among...

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Tuning the stoichiometry and electrical properties of tantalum oxide thin films

Cited by 23 publications

References 38 publications

Tantalum Suboxide Films with Tunable Composition and Electrical Resistivity Deposited by Reactive Magnetron Sputtering

Tantalum Suboxide Films with Tunable Composition and Electrical Resistivity Deposited by Reactive Magnetron Sputtering

Oxygen vacancies: The (in)visible friend of oxide electronics

Memristor‐transistor hybrid ternary content addressable memory using ternary memristive memory cell

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