Characterization of transparent conductive ITO, ITiO, and FTO films for application in photoelectrochemical cells

Transparent conductive In(2-x)Sn(x)O3 (ITO) and In(2-x)Ti(x)O3 (ITiO) films were prepared via RF magnetron sputtering on soda-lime glass substrates at 300 degrees C and investigated with respect to their photoelectric conversion performance compared with the commercial F:SnO2 (FTO) glass. The near infrared ray transmittance of ITiO was highest for wavelengths over 1000 nm compared with those of ITO and FTO. Photoelectrochemical cells (PECs) were fabricated using ITiO film, ITO film, and FTO glass. The photoelectric conversion efficiency (eta) of the PECs samples using ITiO was 5.64%, whereas 2.73% was obtained from the PEC samples with ITO, both at 100 mW/cm2 light intensity. The impedance measurement was also used to explain the electrochemical performance of the PECs with various TCO glasses.     

Improved electrical and optical properties of ITO/Ag/ITO films by using electron beam irradiation and their application to ultraviolet light-emitting diode as highly transparent p-type electrodes

We have investigated the effect of insertion of a Ag layer in ITO film as well as electron beam irradiation to the multilayer films on the electrical and optical properties of the ITO-based multilayer deposited by magnetron sputtering method at room temperature. Inserting a very thin Ag layer between ITO layers resulted in a significant decrease in sheet resistance and increased the optical band gap of the ITO/Ag/ITO multilayer to 4.35 eV, followed by a high transparency of approximately 80% at a wavelength of 375 nm. We have also fabricated ultraviolet light-emitting diodes (LED) by using the ITO/Ag/ITO p-type electrode with/without electron beam irradiation. The results show that the UV-LEDs having ITO/Ag/ITO p-electrode with electron beam irradiation produced 19% higher optical output power due to the low absorption of light in the p-type electrode.     

Study on inverse spinel zinc stannate, Zn2SnO4, as transparent conductive films deposited by rf magnetron sputtering

Inverse spinel zinc stannate (Zn₂SnO₄, ZTO) films were deposited onto fused quartz glass substrates heated at 800 °C by rf magnetron sputtering using a ceramic ZTO target (Zn:Sn = 2:1). H₂ flow ratios [H₂/(Ar + H₂)] were controlled from 0 to 30% during the depositions. ZTO films deposited at 800 °C possessed a polycrystalline inverse spinel structure. The lowest resistivity of 1.1 × 10^− 2 Ω cm was obtained for a ZTO film deposited at 20% H₂ flow ratio. The transmittance of the ZTO film was approximately 80% in the visible region.     

Das Integrationspotential mesoporöser SiO2‐Schichten als ultra‐low‐k Dielektrikum. Mesoporous SiO2 as low‐k dielectric for integration in Cu/low‐k interconnect systems

Successful integration of ultra low‐k materials in Cu/low‐k interconnect systems plays a key role for next generation of highly integrated circuits of the 65nm generation with high operation speed. The main goal of this is the improvement of the transmission features of the interconnect system between devices, global wires and systems. Processing by Cu‐DAMASCENE technique requires stability of the dielectric films against chemical, thermal and mechanical attack. To overcome the conventional limitations for processing will be a great challenge for establishing a new dielectric material for integration. The object of this paper is to expose the potential of mesoporous SiO₂ dielectric films concerning functional properties and technological behaviour.     

Thin film fabrication of nano-porous 12CaO·7Al2O3 crystal and its conversion into transparent conductive films by light illumination

Thin film fabrication of crystalline 12CaO·7Al₂O₃ (C12A7) with zeolitic structure was examined, and their electrical and optical properties were measured. Polycrystalline thin films were prepared by post-annealing of amorphous films in oxygen atmosphere at temperatures above 800 °C. Choice of substrates was crucial for obtaining single-phase thin films. Although various oxide substrates (single crystals of Al₂O₃, Y-stabilized ZrO₂, MgO and silica glass) were examined, single-phase films were obtained only for MgO substrates and the other substrates reacted with the CaO component in the films during post-annealing. The optical band gap of C12A7 was evaluated to be 5.9 eV. Hydride ions were incorporated into the film by a thermal treatment in a hydrogen atmosphere at 1200 °C. The resulting transparent thin films were converted into transparent persistent electronic conductors exhibiting an electrical conductivity 6.2×10⁻¹ S cm⁻¹ at 300 K by ultraviolet light illumination. This is the first example of transparent conductive thin film in which conductive areas can be patterned directly by light.     

Grenzflächen‐optimierte Mo/Si Multischichten als Reflektoren für den EUV Spektralbereich. Interface‐optimized Mo/Si multilayers as reflectors for the EUV spectral range

EUV lithography is the most promising technique for the fabrication of semiconductor structures below 50 nm. This requires the use of reflecting multilayers as optical elements. These multilayers must have reflectances as high as possible since it determines the efficiency of the technique and therefore the throughput of a future chip fab. In this work we present investigations on the interface quality of Mo/Si multilayers which are prepared by magnetron sputter deposition. Starting from the two‐component Mo/Si system, that has mainly been optimized with respect to interface roughness, we show that interface interdiffusion can also be reduced by the introduction of tiny barrier layers. In pure Mo/Si multilayers particularly a low Ar sputter gas pressure is important to get smooth layers, whereas the interdiffusion can be reduced by the deposition of C and B₄C barrier layers on the individual interfaces. As result of our work, we have prepared Mo/Si multilayers with outstanding high reflectances: R_EUV = 70.1 % (λ = 13.3 nm, α = 1.5°), R_EUV = 71.4 % (λ = 12.5 nm, α = 22.5°).