title: Structural and Electrical Characterization of SiO2Gate Dielectrics Deposited from Solutions at Moderate Temperatures in Air.
abstract: Silicon dioxide (SiO2) is the most widely used dielectric for electronic applications. It is usually produced by thermal oxidation of silicon or by using a wide range of vacuum-based techniques. By default, the growth of SiO2by thermal oxidation of silicon requires the use of Si substrates whereas the other deposition techniques either produce low quality or poor interface material and mostly require high deposition or annealing temperatures. Recent investigations therefore have focused on the development of alternative deposition paradigms based on solutions. Here, we report the deposition of SiO2thin film dielectrics deposited by spray pyrolysis in air at moderate temperatures of ≈350 °C from pentane-2,4-dione solutions of SiCl4. SiO2dielectrics were investigated by means of UV-vis absorption spectroscopy, spectroscopic ellipsometry, XPS, XRD, UFM/AFM, admittance spectroscopy, and field-effect measurements. Data analysis reveals smooth (RRMS< 1 nm) amorphous films with a dielectric constant of about 3.8, an optical band gap of ≈8.1 eV, leakage current densities in the order of ≈10-7A/cm2at 1 MV/cm, and high dielectric strength in excess of 5 MV/cm. XPS measurements confirm the SiO2stoichiometry and FTIR spectra reveal features related to SiO2only. Thin film transistors implementing spray-coated SiO2gate dielectrics and C60and pentacene semiconducting channels exhibit excellent transport characteristics, i.e., negligible hysteresis, low leakage currents, high on/off current modulation ratio on the order of 106, and high carrier mobility.
authors.affiliation: Engineering Department, Lancaster University , Lancaster LA1 4YR, United Kingdom.|Faculty of Electronics and Computer Engineering, Universiti Teknikal Malaysia Melaka (UTeM) Durian Tunggal, Melaka 76100, Malaysia.
authors.forename: Mazran
authors.initials: M
authors.lastname: Esro
authors.affiliation: Department of Physics, Lancaster University , Lancaster LA1 4YW, United Kingdom.
authors.forename: Oleg
authors.initials: O
authors.lastname: Kolosov
authors.affiliation: Engineering Department, Lancaster University , Lancaster LA1 4YR, United Kingdom.
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Jones
authors.affiliation: Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.|Quantum Nanoelectronics Research Center (QNERC), Tokyo Institute of Technology , 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550, Japan.
authors.forename: William I
authors.initials: WI
authors.lastname: Milne
authors.affiliation: Engineering Department, Lancaster University , Lancaster LA1 4YR, United Kingdom.
authors.forename: George
authors.identifier: 0000-0002-2535-007X
authors.initials: G
authors.lastname: Adamopoulos
mesh_terms: D004560:Electricity; D012825:Silicon / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012996:Solutions; D013696:Temperature
chemical_list: D012996:Solutions; D012822:Silicon Dioxide; D012825:Silicon
keywords: gate dielectrics; silicon dioxide; solution processed electronics; spray pyrolysis; thin film transistors