Properties of Pulsed DC Sputtered Vanadium Oxide Thin Films Using A V2O3 Target for Uncooled Microbolometers PDF Download

Author: Kerry Elizabeth Wells
Publisher:
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Category :
Languages : en
Pages :

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Author: Yao Jin
Publisher:
ISBN:
Category :
Languages : en
Pages :

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A vanadium oxide (VO x) thin film is the most common imaging layer used in commercial uncooled focal plane arrays for infrared cameras. These VOx thin films have an x value ranging from 1.3 to 2 and have low resistivity (0.1 to 10 [omega] cm), high temperature coefficient of resistance (TCR) (-2 to -3 %/K), and low 1/f noise. Reactive ion beam sputtering is typically used to deposit these VOx thin films for commercial thermal imaging cameras. However, the reactive ion beam deposition system for the VOx is reported to have less than desirable throughput and a narrow process window. In this work, the potential for reactive pulsed-dc magnetron sputtering of nanocomposite VOx thin films for microbolometer applications was investigated. VOx thin films with resistivity from 10-4 to 105 [omega] cm with a TCR from 0 to -4.3 %/K were deposited by reactive sputtering from a metallic vanadium target in argon/oxygen mixtures with substrate bias. Magnetron sputtered VOx shows bolometric properties comparable to those of commercial-grade IBD prepared VOx. Important limitations for manufacturing implementation of reactive magnetron sputtering such as hysteresis oxidation and non-uniform oxidation of the vanadium target surface were evaluated. The VOx film deposition rate, resistivity, and temperature coefficient of resistance were correlated to oxygen to argon ratio, processing pressure, target-to-substrate distance, and oxygen inlet positions. To deposit VOx in the resistivity range of 0.1--10 [omega] cm with good uniformity and process control, it was found that a lower processing pressure, larger target-to-substrate distance, and an oxygen inlet near the substrate are useful. Other processing methods employing magnetron sputtering were investigated such as co-sputtering of V and V2O5 target, sputtering from a VC target, a V2O5 target, and a V2Ox target but initial investigation of these methods did not yield a superior process to the simple sputtering of a pure metallic vanadium target. Another technique, biased target ion beam deposition (BTIBD), was investigated for deposition VOx thin films with potential alloy additions. In this BTIBD system, ions with energy lower than 25 eV were generated remotely and vanadium targets are negatively biased independently for sputtering. High TCR (

Author: Bryan Douglas Gauntt
Publisher:
ISBN:
Category :
Languages : en
Pages : 170

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Author: Kaushik Chhotani
Publisher:
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Category : Thin films
Languages : en
Pages : 126

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Languages : en
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The present work is devoted to the experimental study of the MI transition in V2O3 thin films, grown on different substrates. The main goal of the work was to develop a technology of growth of V2O3 thin films on substrates with different electrical and structural properties (diamond and LiNbO3), designed for specific applications. The structural and electrical properties of the obtained films were characterized in detail with a special focus on their potential applications. The MIT of V2O3 was investigated by SAW using first directly deposited V2O3 thin film onto a LiNbO3 substrate.

Author: Hernan M. R.
Publisher:
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Category : Science
Languages : en
Pages :

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This chapter describes a new deposition method proposed to achieve Vanadium Oxide VOx/V2O5 thin films with high temperature coefficient of resistance (TCR), intended to be used as functional material in IR microsensors (bolometers). The main aim of the work is to attain a deposition method compatible with the lift-off microstructuring technique in order to avoid the use of a reactive-ion etching (RIE) process step to selectively remove the VOx/V2O5 deposited layer in the course of the definition of the bolometer geometry, preventing the harmful effects linked to the spatial variability and the lack of selectivity of the RIE process. The proposed technique makes use of a two-stage process to produce the well-controlled VOx or V2O5 thin films by applying a suitable thermal annealing to a previously deposited layer, which was obtained before at room temperature by RF magnetron sputtering and patterned by lift-off. A set of measurements has been carried out with thin films attained in order to check the quality and properties of the materials achieved with this method. The results reached with V2O5 pure phase films are consistent with a charge transport model based on the small polarons hopping derived from Mott's model under the Schnakenberg form.

Author: Mengyang Zou
Publisher:
ISBN:
Category : Bolometer
Languages : en
Pages : 68

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Microbolometer IR imagers consist of an array of thermally sensitive pixels that change resistance as infrared radiation is focused onto the array. Commonly used thermoresisitive materials are amorphous silicon (a-Si) and vanadium oxide (VOx). Despite their use in image sensors, these films are extremely difficult to produce with widely varying process conditions being reported in the literature. Therefore, the goal of this work was to examine the process windows of some of these methods, including novel approaches such as oxygen ion assisted deposition (IAD), aluminum-induced crystallization and glancing angle deposition. Among the thermoresistive materials, vanadium oxide has been widely used in microbolometers due to their excellent thermoresistive properties, relatively fast thermal time constants and high temperature coefficient of resistance (TCR). In our work, we examined different physical vapor deposition methods including: RF reactive sputtering of metallic vanadium to produce vanadium oxide, thermal evaporation of vanadium films and subsequent oxidation, and Oxygen Ion-Assisted Deposition (IAD) of e-beam evaporated vanadium. In addition to VOx, amorphous silicon is also desirable because it can be easily integrated into the CMOS fabrication processes more than VOx. The hydrogenated amorphous silicon produced by PECVD has a high TCR and a relatively high optical absorption coefficient. In addition to PECVD, we used a glancing angle deposition and also examined a novel approach to create polycrystalline silicon from aluminum-induced crystallization.

Author: Wing Andy Li
Publisher: Open Dissertation Press
ISBN: 9781374735187
Category : Science
Languages : en
Pages : 118

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This dissertation, "The Electrical Properties of Vanadium Oxide Films" by Wing, Andy, Li, 李榮, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. DOI: 10.5353/th_b3120506 Subjects: Sputtering (Physics) Vanadium oxide Amorphous substances

Author: Velaphi Msomi
Publisher: LAP Lambert Academic Publishing
ISBN: 9783843377720
Category :
Languages : en
Pages : 76

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In the last few decades, vanadium dioxide thin films have been synthesized using various methods/equipments. The quality of results coming out from these methods are different. But yet no one has done a comparative study on the quality of the films prepared using at least two or more of these methods/equipments. This book reports about the quality of vanadium dioxide thin films prepared using Inverted cylindrical magnetron sputtering and pulsed laser deposition.

Author: Amber Nicole Reed
Publisher:
ISBN:
Category : Oxide coating
Languages : en
Pages : 48

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