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Hiroshi Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Ultrathin Tantalum Oxide Capacitor Dielectric Layers Fabricated Using Rapid Thermal Nitridation prior to Low Pressure Chemical Vapor Deposition
2016Co-Authors: Satashi Kamiyama, Hiroshi Suzuki, Pierreyves Lesaicherre, Iwao Nishiyama, Akira A Sakai, Akihiko Ishitani *&aposAbstract:We describe the formation of ultrathin tanta lum oxide capacitors, using rapid thermal nitridation of the storage-node polycrystalline-silicon surface prior to low pressure chemical vapor deposition of tanta lum oxide. The amorphous tanta-lum oxide film is deposited on the nitrided polysilicon surface using penta-ethoxy-Tantalum [Ta(OC~Hs)~] and oxygen (09) gas mixture at 470 ~ The films are annealed at 600-900 ~ in dry 02. Densification of the as-deposited film by annealing in dry O2 is indispensable to the formation of highly reliable ultrathin tanta lum oxide capacitors. Dur ing this densification, CH4 and H20 desorb f rom the as-deposited film, and the film crystallizes into an orthorhombic structure. The RTN treatment allows a reduction of the SiO2 equivalent thickness (t~q) of the capacitor dielectric layer and results in superior leakage and reliability characteristics. Highly integrated memory devices, such as 256 Mbit dy-namic random access memories (DRAMs), require very thin dielectric films for three-dimensional stacked or trenched capacitors. 1'2 These memory devices have to hold a sufficient storage charge in a memory cell capacitor to pre-vent soft errors. 3Tantalum oxide films prepared by lo
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extended x ray absorption fine structure analysis of the difference in local structure of Tantalum oxide capacitor films produced by various annealing methods
Applied Physics Letters, 1995Co-Authors: Hidekazu Kimura, Junichiro Mizuki, Satoshi Kamiyama, Hiroshi SuzukiAbstract:Extended x‐ray absorption fine structure (EXAFS) above the Ta L3 edge on Tantalum oxide capacitor films has been measured. Tantalum oxide films were prepared by low‐pressure chemical vapor deposition (CVD) using a Ta(OC2H5)5 and O2 gas mixture. Four kinds of Tantalum oxide films were studied: as‐deposited (amorphous), N2 annealed (crystalline), dry O2 annealed (crystalline), and O2‐plasma annealed (amorphous). From EXAFS analysis, differences in the local structures of Tantalum oxide capacitor films, in terms of oxygen deficiency around Ta, were observed in the various annealed films. The leakage current characteristics of Tantalum oxide capacitors correspond to the differences in the local structures around Ta.
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ulfrathin Tantalum oxide capacitor process using oxygen plasma annealing
Journal of The Electrochemical Society, 1994Co-Authors: Satoshi Kamiyama, Hirohito Watanabe, Akira Sakai, Hidekazu Kimura, Hiroshi Suzuki, Junichiro MizukiAbstract:A highly reliable ultrathin Tantalum oxide capacitor is fabricated by using oxygen-plasma annealing after the film deposition. A Tantalum oxide film is deposited on a nitrided polycrystalline silicon surface using a mixture of pentaethoxy-Tantalum [Ta(OC 2 H 5 ) 5 ] and oxygen gas. The films are annealed in an oxygen-plasma at less than 400 o C. The oxygen-plasma annealing greatly reduces the leakage current through Tantalum oxide capacitors and produces better time-dependent dielectric breakdown characteristics than either dry O 2 annealing or two-step annealing (oxygen-plasma+dry O 2 annealings)
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ultrathin Tantalum oxide capacitor dielectric layers fabricated using rapid thermal nitridation prior to low pressure chemical vapor deposition
Journal of The Electrochemical Society, 1993Co-Authors: Satoshi Kamiyama, Akira Sakai, Hiroshi Suzuki, Pierreyves Lesaicherre, Iwao Nishiyama, Akihiko IshitaniAbstract:We describe the formation of ultrathin Tantalum oxide capacitors, using rapid thermal nitridation of the storage-node polycrystalline-silicon surface prior to low pressure chemical vapor deposition of Tantalum oxide. The amorphous Tantalum oxide film is deposited on the nitrided polysilicon surface using penta-ethoxy-Tantalum [Ta(OC 2 H 5 ) 5 ] and oxygen (O 2 ) gas mixture at 410 o C. The films are annealed at 600-900 o C in dry O 2 . Densification of the as-deposited film by annealing in dry O 2 is indispensable to the formation of highly reliable ultrathin Tantalum oxide capacitors. During this densification, CH 4 and H 2 O desorb from the as-deposited film, and the film crystallizes into an orthorhombic structure
In Seok Oh - One of the best experts on this subject based on the ideXlab platform.
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fabrication and mechanical properties of powder metallurgy Tantalum prepared by hot isostatic pressing
International Journal of Refractory Metals & Hard Materials, 2015Co-Authors: Youngsam Kwon, In Seok OhAbstract:Abstract The fabrication process of a powder metallurgy (P/M) Tantalum product with full density and fine microstructure was developed by using cold and hot isostatic pressing techniques. In order to increase the compact density and make the uniform density distribution, cold isostatic pressing (CIPing) of Tantalum powders was conducted. Prior to hot isostatic pressing (HIPing), the CIPed billet was encapsulated and degassed to remove the contaminants in the container. After degassing, HIPing was performed twice and full densification of the Tantalum powders was accomplished, regardless of powder size. The effect of processing conditions on the microstructure and mechanical properties of P/M Tantalum billets was investigated. As the number of processing steps and temperature increased, the grain size of HIPed Tantalum billets increased. Moreover, contrary to the Hall–Petch relation, the mechanical strength was increased in spite of increasing the grain size. This is because the oxygen content of the billets increased with rising in temperature and the number of processing steps. Therefore, in case of Tantalum, it is found that the mechanical properties of Tantalum may be highly influenced by the amount of interstitial elements, especially oxygen, rather than microstructural properties.
J J Krygier - One of the best experts on this subject based on the ideXlab platform.
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clinical validation of a structural porous Tantalum biomaterial for adult reconstruction
Journal of Bone and Joint Surgery American Volume, 2004Co-Authors: Dennis J Bobyn, Robert A Poggie, J J Krygier, David G Lewallen, Arlen D Hanssen, Randall J Lewis, Anthony S Unger, Thomas Okeefe, Michael J Christie, S NasserAbstract:Various porous coatings—most notably, those manufactured by the sintering of cobalt-chrome or titanium beads and the diffusion bonding of titanium fiber wires—have been utilized for the biologic attachment of orthopaedic implants during the past three decades1. About ten years ago, a novel porous biomaterial made from commercially pure Tantalum2-5 with a unique set of physical and mechanical properties was developed. Compared with conventional porous coatings, this material possesses higher volume porosity, more freely communicating pores, a higher coefficient of friction against bone, and a lower bulk stiffness (Fig. 1). In addition, the material is structural in that it has sufficient strength to enable the manufacture of implants without the need for a supportive solid metal substrate. Fig. 1 Top, Scanning electron micrograph illustrating the three-dimensional, open-pored structure of the porous Tantalum biomaterial. The inset highlights the slight microtexture on the Tantalum struts that results from the manufacturing process. Bottom, Monoblock cups manufactured by partial infiltration of polyethylene into the porous Tantalum shell by direct compression-molding. Previous studies have characterized the physical and mechanical properties of porous Tantalum6,7. Histologic analyses of the bone and fibrous ingrowth responses to various implants in animals have indicated a propensity for rapid infiltration of porous Tantalum with healing tissue and relatively rapid rates of mechanical attachment8-14. Recent cell-culture studies have characterized the osteoblastic response to commercially pure Tantalum, adding further confirmation to its long history as a biocompatible elemental metal2-5,15. Porous Tantalum has been utilized for a wide variety of clinical applications since 1997, including joint replacement, reconstruction following tumor resection, the treatment of avascular necrosis of the femoral head, and spine fusion. The purpose of the present study was to document the clinical results obtained with porous …
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fibrous tissue ingrowth and attachment to porous Tantalum
Journal of Biomedical Materials Research, 2000Co-Authors: S A Hacking, J D Bobyn, K K Toh, Michael Tanzer, J J KrygierAbstract:This study determined the soft tissue attachment strength and extent of ingrowth to a porous Tantalum biomaterial. Eight dorsal subcutaneous implants (in two dogs) were evaluated at 4, 8, and 16 weeks. Upon retrieval, all implants were surrounded completely by adherent soft tissue. Implants were harvested with a tissue flap on the cutaneous aspect and peel tested in a servo-hydraulic tensile test machine at a rate of 5 mm/min. Following testing, implants were dehydrated in a solution of basic fuschin, defatted, embedded in methylmethacrylate, and processed for thin-section histology. At 4, 8, and 16 weeks, the attachment strength to porous Tantalum was 61, 71, and 89 g/mm respectively. Histologic analysis showed complete tissue ingrowth throughout the porous Tantalum implant. Blood vessels were visible at the interface of and within the porous Tantalum material. Tissue maturity and vascularity increased with time. The tissue attachment strength to porous Tantalum was three- to six-fold greater than was reported in a similar study with porous beads. This study demonstrated that porous Tantalum permits rapid ingrowth of vascularized soft tissue, and attains soft tissue attachment strengths greater than with porous beads.
Satoshi Kamiyama - One of the best experts on this subject based on the ideXlab platform.
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extended x ray absorption fine structure analysis of the difference in local structure of Tantalum oxide capacitor films produced by various annealing methods
Applied Physics Letters, 1995Co-Authors: Hidekazu Kimura, Junichiro Mizuki, Satoshi Kamiyama, Hiroshi SuzukiAbstract:Extended x‐ray absorption fine structure (EXAFS) above the Ta L3 edge on Tantalum oxide capacitor films has been measured. Tantalum oxide films were prepared by low‐pressure chemical vapor deposition (CVD) using a Ta(OC2H5)5 and O2 gas mixture. Four kinds of Tantalum oxide films were studied: as‐deposited (amorphous), N2 annealed (crystalline), dry O2 annealed (crystalline), and O2‐plasma annealed (amorphous). From EXAFS analysis, differences in the local structures of Tantalum oxide capacitor films, in terms of oxygen deficiency around Ta, were observed in the various annealed films. The leakage current characteristics of Tantalum oxide capacitors correspond to the differences in the local structures around Ta.
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ulfrathin Tantalum oxide capacitor process using oxygen plasma annealing
Journal of The Electrochemical Society, 1994Co-Authors: Satoshi Kamiyama, Hirohito Watanabe, Akira Sakai, Hidekazu Kimura, Hiroshi Suzuki, Junichiro MizukiAbstract:A highly reliable ultrathin Tantalum oxide capacitor is fabricated by using oxygen-plasma annealing after the film deposition. A Tantalum oxide film is deposited on a nitrided polycrystalline silicon surface using a mixture of pentaethoxy-Tantalum [Ta(OC 2 H 5 ) 5 ] and oxygen gas. The films are annealed in an oxygen-plasma at less than 400 o C. The oxygen-plasma annealing greatly reduces the leakage current through Tantalum oxide capacitors and produces better time-dependent dielectric breakdown characteristics than either dry O 2 annealing or two-step annealing (oxygen-plasma+dry O 2 annealings)
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ultrathin Tantalum oxide capacitor dielectric layers fabricated using rapid thermal nitridation prior to low pressure chemical vapor deposition
Journal of The Electrochemical Society, 1993Co-Authors: Satoshi Kamiyama, Akira Sakai, Hiroshi Suzuki, Pierreyves Lesaicherre, Iwao Nishiyama, Akihiko IshitaniAbstract:We describe the formation of ultrathin Tantalum oxide capacitors, using rapid thermal nitridation of the storage-node polycrystalline-silicon surface prior to low pressure chemical vapor deposition of Tantalum oxide. The amorphous Tantalum oxide film is deposited on the nitrided polysilicon surface using penta-ethoxy-Tantalum [Ta(OC 2 H 5 ) 5 ] and oxygen (O 2 ) gas mixture at 410 o C. The films are annealed at 600-900 o C in dry O 2 . Densification of the as-deposited film by annealing in dry O 2 is indispensable to the formation of highly reliable ultrathin Tantalum oxide capacitors. During this densification, CH 4 and H 2 O desorb from the as-deposited film, and the film crystallizes into an orthorhombic structure
Youngsam Kwon - One of the best experts on this subject based on the ideXlab platform.
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fabrication and mechanical properties of powder metallurgy Tantalum prepared by hot isostatic pressing
International Journal of Refractory Metals & Hard Materials, 2015Co-Authors: Youngsam Kwon, In Seok OhAbstract:Abstract The fabrication process of a powder metallurgy (P/M) Tantalum product with full density and fine microstructure was developed by using cold and hot isostatic pressing techniques. In order to increase the compact density and make the uniform density distribution, cold isostatic pressing (CIPing) of Tantalum powders was conducted. Prior to hot isostatic pressing (HIPing), the CIPed billet was encapsulated and degassed to remove the contaminants in the container. After degassing, HIPing was performed twice and full densification of the Tantalum powders was accomplished, regardless of powder size. The effect of processing conditions on the microstructure and mechanical properties of P/M Tantalum billets was investigated. As the number of processing steps and temperature increased, the grain size of HIPed Tantalum billets increased. Moreover, contrary to the Hall–Petch relation, the mechanical strength was increased in spite of increasing the grain size. This is because the oxygen content of the billets increased with rising in temperature and the number of processing steps. Therefore, in case of Tantalum, it is found that the mechanical properties of Tantalum may be highly influenced by the amount of interstitial elements, especially oxygen, rather than microstructural properties.
