Atsutoshi Inokuchi

Low-Dielectric-Constant Nonporous Fluorocarbon Films for Interlayer Dielectric

Low-dielectric-constant (k<2.0) nonporous fluorocarbon films are formed using a new microwave-excited low electron temperature and high-density plasma system with a dual-shower-plate structure. In the new system, the material gas (C5F8) is supplied by a lower shower plate inserted in the diffusion plasma region of very low electron temperature (around 1–2 eV). An upper shower plate is used for supplying the plasma excitation gas in a uniform downflow in the chamber. Since such a gas flow pattern can prevent the penetration of the material gas into the plasma excitation region, the overdecomposition of the material gas can be markedly suppressed as compared with that in the case of using conventional plasma systems such as an electron cyclotron resonance (ECR) plasma source. As a result, fluorocarbon films can be formed by maximizing the original characteristics of material gases. The fluorocarbon films formed using the new system have not only low k but also low leakage current density, sufficient mechanical strength, strong adhesion, high heat resistance and good surface smoothness. Therefore, such films can be used in interlayer dielectrics in ultralarge-scale integration (ULSI) devices.

Characterization of Zinc Oxide Films Grown by a Newly Developed Plasma Enhanced Metal Organic Chemical Vapor Deposition Employing Microwave Excited High Density Plasma

The radical reaction based semiconductor manufacturing has been applied to silicon device process. Such as SiO2 and Si3N4 can be formed at low temperatures of under 500–600 °C. In this study, we applied radical reaction based semiconductor manufacturing to compound semiconductor of ZnO. The characteristics of ZnO films grown by a newly developed plasma enhanced metal organic chemical vapor deposition (MOCVD) employing microwave excited high-density plasma are good. The film formed on a-plane sapphire is epitaxially oriented in c-axis direction, and the composition is similar to ZnO substrate grown by hydrothermal method. The mobility of grown film at around 400 °C is 23 cm2/(Vs), and it is increased to 46 cm2/(Vs) by 700 °C annealing. The carbon concentration in the films can be reduced by the selection of a zinc precursor and the optimization of process conditions. The active species of plasma are effective for the crystallization of films.

Light-Emitting Diode Based on ZnO by Plasma-Enhanced Metal–Organic Chemical Vapor Deposition Employing Microwave Excited Plasma

In this paper we describe the growth of nitrogen doped zinc oxide (ZnO) films on single crystal ZnO substrates by plasma-enhanced metal–organic chemical vapor deposition (PE-MOCVD) employing microwave excited high-density plasma. We used Dimethylzinc (DMZ) as a Zinc precursor, and six different types of oxygen and nitrogen precursors: O2+N2, NO, N2O, O2+NH3, NO2, and O2. This paper considers the effects of nitrogen precursor material and utilizing the plasma on the structural properties and the nitrogen concentration by atomic force microscope and secondary ion mass spectrometry. It was only when using plasma and NO2 that the nitrogen (N) doped ZnO film with the steps and terraces surface structure of two-dimensional growth could be formed by our growth method. Furthermore, we fabricated a homostructural LED comprising the N-doped ZnO film and n-type ZnO substrate, and we achieved electroluminescence (EL) in forward bias at room-temperature (RT) and the current–voltage rectifying characteristics.

Evaluation of Narrow Gap Filling Ability in Shallow Trench Isolation by Organosiloxane Sol-Gel Precursor

Kohei Watanuki, Atsutoshi Inokuchi, Akinori Banba, Nobuyuki Manabe, Hirokazu Suzuki, Tadashi Koike, Tatsuhiko Adachi, Tetsuya Goto, Akinobu Teramoto, Yasuyuki Shirai, Shigetoshi Sugawa and Tadahiro Ohmi 1 New Industry Creation Hatchery Center, Tohoku University, Aza-Aoba 6-6-10, Aramaki, Aobaku, Sendai 980-8579, Japan 2 Ube-nittou kasei co., ltd., 2-1-1 Yabutanishi Gifu 5008386 Japan 3 Graduate School of Engineering, Tohoku University, Aza-Aoba 6-6-11, Aramaki, Aobaku, Sendai 980-8579, Japan 4 WPI Research Center Aza-Aoba 6-6-10, Aramaki, Aobaku, Sendai 980-8579, Japan

Establishment of very uniform gas-flow pattern in the process chamber for microwave-excited high-density plasma by ceramic shower plate

The authors developed a ceramic upper shower plate used in the microwave-excited high-density plasma process equipment incorporating a dual shower-plate structure to establish a very uniform gas-flow pattern in the process chamber. Thousands of very fine gas-injection holes are implemented on this Al2O3 upper shower plate with optimized allocation to establish a uniform gas-flow pattern of plasma-excitation gases and radical-generation gases for generating intended radicals in the plasma-excitation region. The size of these fine holes must be 50μm or less in diameter and 8mm or more in length because these holes perform an essential role: They completely avoid the plasma excitation in these fine holes and upper gas-supply regions resulting from the plasma penetration into these regions from excited high-density plasma, even if very high-density plasma greater than 1×1012cm−3 is excited just under the ceramic upper shower plate by microwaves supplied from the radial line slot antenna. On the other hand, va...

Effects of Ion-Bombardment-Assist and High Temperature on Growth of Zinc Oxide Films by Microwave Excited High Density Plasma Enhanced Metal Organic Chemical Vapor Deposition

In this paper we describe the growth of zinc oxide (ZnO) films on a-plane sapphire substrates by plasma enhanced metal organic chemical vapor deposition (PE-MOCVD) employing microwave excited high-density plasma. In detail, we discuss the effects of ion-bombardment-assist and high temperature on structural properties, electrical properties, optical properties, impurity concentration and thermostability by X-ray diffraction (XRD), field emission scanning electron microscopy, Hall effect measurement at room temperature, photoluminescence, secondary ion mass spectrometry and thermal desorption spectroscopy. Ion-bombardment energy is controlled by the condition of radio-frequency (RF) self bias. Moderate ion-bombardment enhances crystallinity, mobility and thermostability, and reduces concentrations of carbon and hydrogen in the films. By raising the growth temperature up to 550 °C, the qualities of films are improved. High quality ZnO film was successfully grown at 550 °C, which is a relatively low temperature compared to general MOCVD. Its full width at half maximum (FWHM) of XRD (0002) rocking curve, carrier concentration and mobility are 0.12°, 5×1016/cm3, and 89 cm2/(Vs), respectively.

Electrical Properties of Metal-Oxide-Containing SiO2 Films Formed by Organosiloxane Sol–Gel Precursor

High-quality SiO2 film formation is important for many applications, such as large-scale integration (LSI) circuit and micro-electro-mechanical system (MEMS) industries. We evaluated the structural and electrical insulation properties of SiO2 films using an organosiloxane-based silica sol–gel precursor derived from a mixture of tetraethoxysilane (TEOS) and methyltrimethoxysilane (MTMS) by changing the molar ratio of TEOS/MTMS. This sol–gel precursor was converted not only to a low-dielectric-constant film with a relative dielectric constant of 2.8 but also to a dense SiO2 film by optimizing baking conditions. The dense SiO2 film from this sol–gel precursor has excellent dielectric characteristics of low leakage current density and high breakdown voltage, whose values are comparable to those of thermal oxide SiO2 films. Furthermore, the breakdown field intensity of these films was improved by adding a small amount of metal oxides, such as TiO2, HfO2, and ZrO2. A maximum breakdown field intensity of 15 MV/cm can be achieved in the case of 10% TiO2 addition.

Light-emitting Diode based on ZnO by Plasma Enhanced MOCVD Employing Microwave Exited Plasma

New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aza Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan Phone: +81-22-795-3977 E-mail: hirokazu.asahara@dsn.rohm.co.jp Graduate School of Engineering, Tohoku University, 6-6-05 Aza Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan ROHM Co., Ltd., 21 Saiin Mizosaki-cho, Ukyo-ku, Kyoto 615-8585, Japan Tokyo Electron Ltd., 650 Mitsusawa, Hosaka, Nirasaki, Yamanashi 407-0192, Japan WPI Research Center, Tohoku University, 6-6-10 Aza Aoba, Aramaki, Aoba-ku, Sendai 980-8579, Japan

Effects of Ion-Bombardment-Assist and High Temperature on Growth of Zinc Oxide Films by Microwave Excited High Density Plasma Enhanced MOCVD

Zinc Oxide Films by Microwave Excited High Density Plasma Enhanced MOCVD Hirokazu Asahara, Atsutoshi Inokuchi, Kohei Watanuki, Masaki Hirayama, Akinobu Teramoto, and Tadahiro Ohmi New Industry Creation Hatchery Center, Tohoku University, 6-6-10 Aza Aoba, Aramaki, Aoba-ku, Sendai, 980-8579, Japan Phone: +81-22-795-3977, Fax: +81-22-795-3986, E-mail: asahara@fff.niche.tohoku.ac.jp ROHM Co., Ltd., 21, Saiin Mizosaki-cho, Ukyo-ku, Kyoto 615-8585, Japan Tokyo Electron, Ltd., Mitsusawa 650, Hosaka, Nirasaki, Yamanashi 407-0192, Japan Ube Industries, Ltd., 1978-10, Kogushi, Ube, Yamaguchi 755-8633, Japan