Tantalum oxide films

Tantalum oxide film, 24 314 Tantalum oxides, 24 322, 334 Tantalum pentachloride, 24 335 Tantalum pentafluoride, 24 334-335 Tantalum pentoxide, electrochemical reduction of, 24 322 Tantalum powder, 24 323, 324-325 capacitor-grade, 24 326 safety of, 24 333-334 Tantalum products, world shipments of, 24 331t... 

White et al. studied electron transfer reactions at a tantalum surface covered by 2.5 nm of native tantalum-(V)-oxide (42). The SECM detected microscopic electroactive sites with a diameter between 4 and 100 /rm. Interestingly, some sites turned out to be active only for the reduction of Ru(NI lit, while others were also capable of oxidizing iodide. The authors studied the kinetics of mediator interaction under various sample potentials and locations in detail to determine parameters relevant for the growth of such tantalum oxide films. An example is given in Figure 17. 

With the more active metals, such as aluminum, titanium, and tantalum, oxide films form immediately on contact with air and behave as passive films in aqueous solutions. In the case of tantalum, the passive film is protective over the entire pH range in other cases, the films may... 

Schematic representation of a metal-arch capacitance transducer according to Jones et al. [245]. This capacitance transducer is of the variable-area electrode type. A tantalum/tantalum oxide film structure is deposited onto a flat glass substrate to obtain a suitably flat surface for contact with a flexible electrode which may be a thin metal foil possibly deposited in the shape of a dome or an arch...

This chapter discusses the preparation of tantalum oxide thin films using the sol-gel method, which we believe is promising as a practical method for producing dielectric thin films whose dielectric constants and breakdown voltages are both comparatively high. Tantalum oxide films are good candidates for insulators in LSI devices, EL devices, and film capacitors [4]. Reports on the for-... 

Tantalum oxide films prepared by the sol-gel method are amorphous fi-om room temperature to 600°C and are completely crystallized at 720°C. 

Fig. 11. SEM micrograph of cross-sectional structure and TbF-SIMS depth profiling data of tantalum oxide films grown for different times, (a) Close-up of the edge of a partially detached 5 min oxide film, (b) Depth profile of a film grown for 1 min. (c) Depth profile of a film grown for 10 min. (d) Depth profile of a film grown for 20 min. (Reproduced with permission from Ref. 76. Copyright 2008 American Chemical Society.)...

Singh S, Greiner MT, Kruse P. (2007) Robust inorganic membranes from detachable ultra-thin tantalum oxide films. Nano Lett . 2676—2583. 

Ohishi T., Maekawa S., Katoh A. Synthesis and properties of tantalum oxide films prepared by the sol-gel method using photo-irradiation. J. Non-Cryst. Sohds 1992 147 148 493-498 Ohishi T., Kato A. Photopatteming of tantalum oxide films by a sol-gel method using a KrF excimer laser. Br. Ceram. Trans. 1993 92 79-80... 

Ozer N., He Y., Lampert C.M. Ionic conductivity of tantalum oxide films prepared by the sol-gel process for electrochromic devices. Proceedings of SPIE Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIII, 1994 2255 456 66 Ozer N., Lampert C.M. Electrochemical lithium insertion in sol-gel deposited LiNbOs films. Sol. 

Thus the oxidizing effect of nitric acid apparently helps to stabilize the protective tantalum oxide film on the metal. 

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