Structural and electrical characterization of SiO2 gate dielectrics deposited from solutions at moderate temperatures in air

Mazran Esro, Oleg Kolosov, Peter J. Jones, William I. Milne, George Adamopoulos*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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 vacuumbased techniques. By default, the growth of SiO2 by 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 SiO2 thin film dielectrics deposited by spray pyrolysis in air at moderate temperatures of ≈350 °C from pentane-2,4-dione solutions of SiCl4. SiO2 dielectrics 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 ≈10-7 A/cm2 at 1 MV/cm, and high dielectric strength in excess of 5 MV/cm. XPS measurements confirm the SiO2 stoichiometry and FTIR spectra reveal features related to SiO2 only. Thin film transistors implementing spray-coated SiO2 gate dielectrics and C60 and 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.

Original languageEnglish
Pages (from-to)529-536
Number of pages8
JournalACS Applied Materials and Interfaces
Volume9
Issue number1
DOIs
Publication statusPublished - 11 Jan 2017
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

Keywords

  • Gate dielectrics
  • Silicon dioxide
  • Solution processed electronics
  • Spray pyrolysis
  • Thin film transistors

ASJC Scopus subject areas

  • General Materials Science

Cite this