Nano crystalline zinc oxide (ZnO) is deposited by room temperature atomic layer deposition (RT-ALD) using dimethylzinc and a plasma excited humidified Ar without thermal treatments. The TEM observation indicated that the deposited ZnO films were crystallized with grain sizes of ∼20 nm on Si in the course of the RT-ALD process. The crystalline ZnO exhibited semiconducting characteristics in a thin film transistor, where the field-effect mobility was recorded at 1.29×10-3cm2/V·s. It is confirmed that the RT deposited ZnO film has an anticorrosion to hot water. The water vapor transmission rate of 8.4×10-3g·m-2·day-1 was measured from a 20 nm thick ZnO capped 40 nm thick Al2O3 on a polyethylene naphthalate film. In this paper, we discuss the crystallization of ZnO in the RT ALD process and its applicability to flexible electronics.

This paper discusses Mixed Signal LSI technology with embedded power transistors. Trends in Mixed Signal LSI technology are explained at first. Mixed signal LSI technology has proceeded with the help of fine fabrication technology and SOI technology. The BEOL transistor is a new development, which uses InGaZnO (IGZO) as its TFT channel material. The BEOL transistor is one future device which enables 3D IC and chip shrinking technology.

We report on the fabrication of coplanar dual-gate ZnO thin-film transistors with 200-nm thickness SiNx for both top and bottom dielectrics. The ZnO film was deposited by RF magnetron sputtering on SiO2/Si substrates at 100. And the thickness of ZnO film is compared with 100-nm and 40-nm. This TFT has a channel width of 100-µm and channel length of 5-µm. The fabricated coplanar dual-gate ZnO TFTs of 40-nm-thickness exhibits a field effect mobility of about 0.29 cm2/V s, a subthreshold swing 420 mV/decade, an on-off ratio 2.7107, and a threshold voltage 0.9 V, which are greatly improved characteristics, compared with conventional bottom-gate ZnO TFTs.

Crystallization of amorphous silicon on oxide semiconductors using rapid-thermal annealing in vacuum is investigated. A 30 nm n-type amorphous silicon (a-Si) is deposited on zinc-oxide (ZnO) and aluminum doped zinc-oxide (ZnO:Al) by PECVD on glass substrate. Rapid-thermal annealing for 30 min to 180 min of a-Si on ZnO and ZnO:Al were performed at 600. It is found that crystallization of a-Si on oxide semiconductors can be done in shorter time than that of standard solid-phase crystallization (SPC) of amorphous silicon on glass substrate at 600. It has been verified using Raman spectroscopy that a-Si on ZnO:Al changes into polycrystalline silicon (poly-Si) in 30 min at 600.

Novel thermopiles based on modulation doped AlGaAs/InGaAs, AlGaN/GaN, and ZnMgO/ZnO heterostructures are proposed and designed for the first time, for uncooled infrared image sensor application. These devices are expected to offer high performances due to both the superior Seebeck coefficient and the excellently high mobility of 2DEG and 2DHG due to high purity channel layers at the heterojunction interface. The AlGaAs/InGaAs thermopile has the figure-of-merit Z of as large as 1.110-2/K (ZT = 3.3 over unity at T = 300 K), and can be realized with a high responsivity R of 15,200 V/W and a high detectivity D* of 1.8109 cmHz1/2/W with uncooled low-cost potentiality. The AlGaN/GaN and the ZnMgO/ZnO thermopiles have the advantages of high sheet carrier concentration due to their large polarization charge effects (spontaneous and piezo polarization charges) as well as of a high Seebeck coefficient due to their strong phonon-drag effect. The high speed response time τ of 0.9 ms with AlGaN/GaN, and also the lower cost with ZnMgO/ZnO thermopiles can be realized. The modulation-doped heterostructure thermopiles presented here are expected to be used for uncooled infrared image sensor applications, and for monolithic integrations with other photon detectors such as InGaAs, GaN, and ZnO PiN photodiodes, as well as HEMT functional integrated circuit devices.

Ga-doped ZnO thin films were prepared by RF magnetron sputtering. The effects of adding H2 to pure Ar sputtering gas were investigated. In the case of pure Ar at 2 Pa, the resistivity is 7.4510-3 Ωcm, whereas for Ar+1%H2 at 0.3 Pa, it markedly decreases to 2.5210-4 Ωcm. In this case, the carrier density and Hall mobility are 1.121021 cm-3 and 23.4 cm2/Vs, respectively. This conductive film also exhibits a transmittance of 90% within the visible-wavelength range. The addition of H2 and the decrease in the pressure results in the fabrication of a significantly more transparent and conductive film.

The properties of the surface-conduction electron-emitter display (SED) are mainly decided by the surface-conduction electron emitters (SCE), which are normally made from the expensive metal Pd. In this study, we propose to use metal Zn instead of Pd as the emitter material. Both the device electrode and ZnO thin film are deposited by a sputter, and the electron emitters (SCE) are formed by the electro-forming process. The electron emission characteristic is obtained and the luminescence is observed.

The dependences of the structural, optical and electrical properties of highly transparent conductive Ga-doped ZnO (GZO) films on thickness have been studied. GZO films were prepared on unheated glass, polymethyl methacrylate (PMMA) and cyclo olefin polymer (COP) substrates by ion plating deposition with direct-current arc discharge. Polycrystalline GZO films with good adherence to a substrate having a (0002) preferred orientation have been obtained. Very little difference was found between the resistivity values of the GZO films on the glass substrate and those of the GZO films on the different polymer substrates, at any given film thickness. On both plastic substrates, the resistivity of the GZO films decreased from 210- 3 to 510-4 Ωcm with increasing film thickness.

Break arcs are generated in a DC 42 V-10 A resistive circuit. The contact material is Ag or Ag/ZnO. The number of break operations is two hundreds for each contact material. The motion of break arcs is observed with a high-speed camera. Relationship between the dependence of arc duration on the number of operations and the motion of arc spots is investigated. The following results are shown. For Ag contacts the arc duration is almost constant independent to the number of break operations. For Ag/ZnO contacts, on the other hand, the arc duration changes irregularly to short (59 ms) or long (69 ms) arc-duration after 30th break operation. The moving range of arc spots on contact surfaces is broad for the case of short arc-duration and is narrow for the case of long arc-duration. The cause of the results for Ag/ZnO contacts is considered that the difference of the boiling points of Ag and ZnO leads to the porous structure on the contact surface.

We demonstrate a novel display structure for color electronic paper for the first time. Fully transparent amorphous oxide TFT array is directly deposited onto color filter array and combined with E Ink Imaging Film. Taking advantage of the transparent property of the oxide TFT, the color filter and TFT array are positioned at the viewing side of the display. This novel "Front Drive" display structure facilitates the alignment of the color filter and TFT dramatically.

We present novel semiconductor technologies of ZnO epitaxial films with using laser molecular-beam epitaxy method. Exciting optical properties such as room temperature lasing in ZnO nanocrystalline films and quantum size effects in ZnO/MgxZn1-xO superlattices were observed. By developing crystalline quality with using lattice-matched substrates, we could control resistivity of the doped ZnO films from 10-3 Ωcm to 104 Ωcm. These results would provide us an opportunity to construct a monolithic array consisted of light emitting devices and field effect transistors towards a possible flat panel display.

Ba ferrite films were deposited epitaxially on ZnO underlayer from targets with composition of BaO-6.5Fe2O3 at substrate temperature of 600 using the facing targets sputtering apparatus. The gas mixture of Ar and Xe of 0.18 Pa and O2 of 0.02 Pa was used as the sputtering gas and the dependences of crystallographic and magnetic characteristics on the partial Xe pressure PXe(0.0-0.18 Pa) were investigated. Films deposited at various PXe were composed of BaM ferrite and spinel crystallites, and the minimum centerline average roughness Ra of 8.3 nm was obtained at PXe of 0.10 Pa. Since saturation 4πMs of 5.1 kG and perpendicular anisotropy constant Ku1 of 4.23105 Jm-3 were larger than those of bulk BaM ferrite of 4.8 kG and 3.30105 Jm-3, respectively, these films appeared promising for use as perpendicular recording media.

This paper reports on a new dynamic scanning force microscope (SFM), in which the piezoelectric microcantilever is utilized for the lever excitation and displacement sensing. Piezoelectric cantilevers can detect their deflection without external sensing elements and be vibrated with no oscillator outside. The cantilever integrated with the deflection detector and the oscillator changes the conventional construction of a dynamic SFM and expands its range of applicability. The microcantilever used consists of a ZnO layer sandwiched with Au electrodes deposited on a thin beam of thermally grown SiO2. The length, width and thickness of the lever are 125 µm, 50 µm and 3.5 µm, respectively. We have characterized this cantilever by measuring the charge spectrum and the frequency dependence of the admittance. From the charge spectrum the mechanical quality factor measured 300 in free vibration. Typical piezoelectric constant of the ZnO film was estimated approximately as 80% of single-crystal's value. The piezoelectric cantilever can be vibrated by applying the voltage with the frequency near the resonance to the piezoelectric layer. The excited amplitude per unit voltage at the resonance frequency was calculated as about 5 µm/V. The cantilever amplitude can be detected by measuring the current between electrodes, since the admittance depends on the quality factor. We have constructed a dynamic SFM without external oscillator and detector, and successfully obtained the surface images of a sol-gel derived PZT film in the cyclic contact operation mode. The longitudinal resolution of the SFM system was 0.3 nm at a 125 Hz bandwidth.