Main features and key issues of the vacuum system for large-scale particle accelerators are presented, taking the KEKB vacuum system as an example. Other than its large scale and complexity, a distinctive difference of the accelerator vacuum system from other vacuum systems is the presence of high-energy charged-particle beams in the vacuum chamber (beam pipe). This brings troublesome but interesting problems into the system, such as the gas desorption by the synchrotron radiation from beams, the electro-magnetic interaction between beams and vacuum components and the interaction between beams and electrons or ions. These problems are more obvious on the KEKB vacuum system due to the unprecedented high stored beam current. The vacuum system will become increasingly important in future high-performance accelerators.

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  Spacecrafts are subjected to severe environmental conditions. Loud sound and vibration are generated in their launch, and separation of spacecrafts from a rocket causes a great shock. Moreover, they are exposed to high-vacuum, very low temperature close to absolute zero, high temperature due to solar radiation, and other severe conditions not found on the earth.
  Once spacecrafts are launched, repair of them is almost impossible. So, it is important to make sure spacecrafts will function properly in such environment before lift-off. They are tested using test facilities which simulate the environmental conditions during launch and flight. In particular, this review shows thermal vacuum test and a space chamber, which simulates high-vacuum, very low temperature, and solar radiation.

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  ULVAC has maintained a leading share in the market of sputtering deposition systems for liquid crystal display (LCD) production since 1990, when LCD market started its rapid growth. These systems are used to prepare TFT-array and transparent conductive oxide (TCO) layers in LCD. This document describes the features of our sputtering system and especially focuses on the change in design concept of the system at the Gen. 7 substrate which aimed to achieve the demands for “Simple, Small-footprint and high-productivity”. A total package we propose for the sputtering deposition production, including the target material supply and the system maintenance, is also presented. Finally, recently proposed new materials for TFT are introduced: IGZO, a high mobility TCO material, and Cu alloys for low resistivity wiring.

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  Reactor cleaning processes have been discussed and designed for atomic layer deposition of hafnium oxide film, taking into account the information of silicon epitaxial growth process. One of the key points for designing the reactor cleaning technique is the production of chemical compounds which can be vaporized at low temperatures. Chemical reaction between hafnium oxide and hydrogen chloride was studied and showed that the hafnium chloride was effectively produced by hydrogen chloride gas at temperatures higher than 300°C. The removal of hafnium oxide film deposited in a reactor is expected to be effectively performed at moderately high temperatures.

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  We examined the impact of surface chemical nature prior to atomic layer deposition (ALD) to the electrical properties of high-k gate stacks on Si substrates. We confirmed that poor electrical film quality in ALD-HfO₂ fabricated on H-terminated surfaces is drastically improved by changing the surface species terminating topmost Si bonds to be hydrophilicized. Especially, the high-k gate stacks fabricated on the surfaces chemically controlled by “oxygen-termination” technique showed excellent interfacial electrical quality without creating thick interfacial SiO₂ layer.

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  Growth properties and electrical properties of Pr oxide films by an atomic layer deposition (ALD) technique using Pr(EtCp)₃ are discussed in this paper. Slef-limiting growth of Pr oxide films at a rate of 0.07 nm/cycle and a thickness variation of less than 2% on 3-in. Si wafers were obtained. Polycrystalline cubic Pr₂O₃ films were grown on Si(001) substrates, while epitaxial growth of the cubic Pr₂O₃ film was found on a Si(111) substrate. Relatively fine capacitance-voltage curves were obtained for the Al/ALD-Pr oxide/Si(001) capacitors. The interface state density between the 130°C-grown ALD-Pr oxide film and the Si(001) substrate is about 1×10¹¹ cm⁻² eV⁻¹. The dielectric constant of the ALD-Pr oxide film grown at 250°C was determined to be about 18, assuming that the dielectric constant of the interlayer is similar to that of SiO₂.

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  The Aerosol Deposition Method is a film coating technology where the impact of solid state particles can create a strongly adherent, high-density nano-crystalline ceramic film by gas blasting the submicron-sized ceramic particles on to a surface. The deposition rate is 30∼100 times faster than obtained with conventional thin film technology and the ceramic thin film can be deposited at room temperature. It is expected to reduce energy, cost, difficulty to fabricate the thin or thick film with complicate material compositions and the number of processes during fabricating electronic devices and others, as well as to improve their performances substantially. This technique is particularly useful for fabricating inorganic thick films and producing energy devices. This chapter deals with the mechanism and feature of the AD process first, followed by its application for energy related devices.

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J. Vac. Soc. Jpn., Vol. 53, No. 11 (2010), pp.686-691

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