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

• Published in: Journal of the American Ceramic Society Vol. 94; no. 1; pp. 250 - 254
• Main Authors: Chuang, Shiow-Huey, Hsieh, Min-Lung, Wu, Shih-Chieh, Lin, Hong-Cai, Chao, Tien-Sheng, Hou, Tuo-Hung
• Format: Journal Article
• Language: English
• Published: Malden, USA Blackwell Publishing Inc 01.01.2011; Wiley Subscription Services, Inc
• Subjects: Ceramics; Deposition; Dielectrics; Diffraction; Electrons; Heat treatment; Nickel; Scanning electron microscopy; Sol gel process; Thin films; Titanates; Titanium
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1551-2916.2010.04037.x

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.