Etsuko Nishimura

Structural Change during Annealing of Amorphous Indium-Tin Oxide Films Deposited by Sputtering with H2O Addition

This paper describes the effects of annealing on electric properties and structure of amorphous indium-tin oxide (ITO) films deposited by sputtering at room temperature and with H2O addition. The film resistivity was increased by annealing at 150–200° C; in this temperature range the growth of ITO crystallites dispersed in the amorphous ITO phase was observed. This increased resistivity was found to be due to decreases in both Hall mobility (µ H) and carrier density (n) of the films. Measurements of thermal desorption spectroscopy revealed that two different adsorption states, in terms of H2O molecules which are due to the hydrogen-bonded H2O and OH species, were formed in amorphous ITO films during film deposition and the subsequent annealing process. Factors in the decreases of µ H and n were discussed on the basis of the experimental results obtained.

Effect of microstructures on nanocrystallite nucleation and growth in hydrogenated amorphous indium–tin–oxide films

Hydrogenated amorphous indium–tin–oxide (ITO) films were prepared by a sputtering method at room temperature with H2O addition. The initial stage of thermal crystallization of the amorphous films was investigated after annealing at 150 °C, just below the crystallization temperature. With increasing H2O addition, the growth of crystallites dispersed in the amorphous matrix was suppressed, while the nucleation of crystallites was sharply enhanced. The amount of bonded hydrogen increased and that of oxygen vacancies decreased at the same time, with introducing inhomogeneites in the amorphous matrix. The effect of these microstructural changes on the nucleation and growth process of crystallites embedded in the amorphous solids was discussed based on these experimental results taking into account a recently proposed theoretical prediction to describe the crystallization of disordered solids.

34.5L: Late‐News Paper: High Transmittance Pixel Design of In‐Plane Switching TFT‐LCDs for TVs

Design architecture of realizing high performance IPS-LCDs with a 30% improved transmittance, less color shifting, and faster response time of less than ms 16 in the grayscales was represented. The newly developed pixel structure, consisting of transparent electrodes arranged on organic insulator, improved the transmittance and shielding effect for a data line. Finally, we have developed a 20-inch diagonal wide-XGA LCD to confirm the performance available to flat-panel TVs.

Highly efficient and long life metal–insulator–metal cathodes

The authors improved the emission efficiency and lifetime of metal–insulator–metal cathodes. The drift of the diode current was suppressed by using a thinner tunneling insulator and a lower diode voltage. The cathode with a 7.9-nm-thick tunneling insulator kept the diode current stable at 0.5 A/cm2 for more than 20 000 h, although the initial emission efficiency declined from 2% to less than 0.5%, and the emission current drift increased. The decreased emission efficiency could be enhanced to more than 3% by mixing CsHCO3 into an Au/Pt/Ir multilayer top electrode.

Roles of bonded hydrogens and oxygen vacancies on crystallization of hydrogenated amorphous indium tin oxide (a-ITO:H) films

Abstract Hydrogenated amorphous indium-tin oxide (a-ITO:H) films were made by sputtering at room temperature with H2O partial pressure as a parameter and initial stage of the thermal crystallization was investigated after 1 h annealing at 150°C. The volume fraction of the nanometer sized crystallites embedded in the amorphous host was minimized at a certain H2O pressure. For lower and higher H2O pressure, the causes of the increase in the crystallites after annealing were different: for lower H2O pressure it was due to the increase in size of the crystallites, whereas for higher H2O pressure it was due to the increase in number of the crystallites. The roles of bonded hydrogens and the oxygen vacancies, which increased and decreased with H2O pressure respectively, are discussed considering the kinetic model for nucleation and growth of crystalline particles in amorphous media.

Large‐screen displays using metal—insulator—metal cathode arrays

— Large-screen (32-in. WXGA and 17-in. VGA) displays using metal—insulator—metal (MIM) cathode arrays have been developed. A cathode structure with low-resistance electrodes and low-capacitance emitters shortens signal delay and decreases the voltage drop in large MIM-cathode arrays. By using a dual-scan method, the signal delay was suppressed to less than 30% of the horizontal scan time in the 32-in. WXGA panel. Emission efficiency of the cathode array was improved to 3% by reducing the surface work function of the top electrode from 4.7 to 3.9 eV. The cathode life was also improved to more than 10,000 hours. The display panel incorporating the cathode arrays and high-efficiency P22-phosphor screens with 3-mm spacers showed high screen brightness (average brightness, 378 cd/m2; peak brightness, 832 cd/m2) at an anode voltage of 10 kV.

Properties of SiGe Films Fabricated by Reactive Thermal Chemical Vapor Deposition Using Lamp Heating

The structural and electrical properties of SiGe films deposited by reactive thermal chemical vapor deposition using a lamp heating system with a source gas mixture of GeF4 and Si2H6 were investigated. In the SiGe film depositions with respective GeF4 and Si2H6 flow rates of 0.06 and 3 sccm, the film structure changed from crystalline to amorphous during the film growth. The results of secondary ion mass spectroscopy analysis and high-temperature deposition suggest that the gas phase reactions cause the structural change. To suppress the gas phase reactions, low-pressure depositions are investigated. The SiGe film deposited at a relatively low pressure of 400 Pa shows good crystallinity. The thin-film transistor with this SiGe film also reveals a high p-channel mobility of about 10 cm2V-1s-1.

58.1: Invited Paper: Highly Efficient and Long Life MIM Cathodes for FEDs

The lifetime of MIM cathodes was lengthened to more than 20,000 hours by using a thinner tunneling insulator (6.9 nm), while the emission efficiency was enhanced to more than 3% by mixing CsHCO3 into a Au/Pt/Ir top electrode. The mechanism of long life and high efficiency will be discussed.

Study on SiGe Film Properties Fabricated using a Reactive Thermal CVD Method

1 Materials Research Laboratory, Hitachi, Ltd. Hitachi-shi, 319-1292 Japan Phone: +81-294-52-7555, Fax: +81-294-52-7615, e-mail: masatoshi.wakagi.vd@hitachi.com 2 Central Research Laboratory, Hitachi, Ltd. Kokubunji-shi, 185-8601 Japan 3 Mechanical Engineering Research Laboratory, Hitachi, Ltd. Hitachinaka-shi,312-0034 Japan 4 Imaging Science and Engineering Laboratory, Tokyo Institute of Technology, Yokohama-shi, 226-8530 Japan

Low Resistivity Transparent Indium Tin Oxide (Ito) Films Sputtered At Room Temperature With H 2 O Addition

A new kind of amorphous indium tin oxide (ITO) film with good pattern delineation properties and mass production capability, as well as low resistivity and high transparency has been developed. The film was prepared by a cluster-type DC magnetron sputtering apparatus at room temperature with H 2 O addition to the argon sputtering gas. The amorphous ITO film quality was improved by effective termination of oxygen vacancies with -OH species generated by enhanced decomposition from the added H 2 O in the plasma.