Fabrication and Characterization of High-k Dielectric Nickel Titanate Thin Films Using a Modified Sol–Gel Method


  • D. Damjanovic—contributing editor

  • This work was financially supported by the National Science Council of the Republic of China under grant no. NSC 96-2113-M-390-003.

†Author to whom correspondence should be addressed. e-mail: shchuang@nuk.edu.tw


This research produced high-quality, single-phase nickel titanate (NiTiO3) thin films, a high-k material for gate dielectrics, by a modified sol–gel method. The precursor was prepared by reactions of nickel acetate tetrahydrate and titanium isopropoxide in 2-methoxyethanol with a 1:1 ratio of Ni/Ti in the solution. After coating, the films were post-heat treated between 500° and 900°C. X-ray diffraction indicated that the films deposited at and above 600°C were single-phase nickel titanate. X-ray photoelectron spectra of a typical thin film revealed that the binding energies of Ni 2p3/2 and Ti 2p3/2 electrons were 855.2 and 457.7 eV, respectively. Raman spectra showed eight absorptions between 200 and 800 cm−1. Scanning electron microscope images showed smooth surfaces. Findings showed the dielectric constant of the NiTiO3 film to be 41.36 by capacitance–voltage analysis. The results show that single-phase NiTiO3 film can be prepared by the sol–gel spin coating method and then heat-treated at 600°C.