Area Selective Growth of Titanium Diselenide Thin Films into Micropatterned Substrates by Low-Pressure Chemical Vapor Deposition

DOI: 10.1021/cm402422e
PMID: 24489437

Authors: Sophie L. Benjamin (University of Southampton) , C. H. (kees) De Groot (University of Southampton) , Chitra Gurnani (University of Southampton) , Andrew L. Hector (University of Southampton) , Ruomeng Huang (University of Southampton) , Konstantin Ignatyev (Diamond Light Source) , William Levason (University of Southampton) , Stuart J. Pearce (University of Southampton) , Fiona Thomas (University of Southampton) , Gillian Reid (University of Southampton)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemistry Of Materials , VOL 25 (23) , PAGES 4719 - 4724

State: Published (Approved)
Published: November 2013
Diamond Proposal Number(s): 8211

Abstract: The neutral, distorted octahedral complex [TiCl4(SenBu2)2] (1), prepared from the reaction of TiCl4 with the neutral SenBu2 in a 1:2 ratio and characterized by IR and multinuclear (1H, 13C{1H}, 77Se{1H}) NMR spectroscopy and microanalysis, serves as an efficient single-source precursor for low-pressure chemical vapor deposition (LPCVD) of titanium diselenide, TiSe2, films onto SiO2 and TiN substrates. X-ray diffraction patterns on the deposited films are consistent with single-phase, hexagonal 1T-TiSe2 (P3̅m1), with evidence of some preferred orientation of the crystallites in thicker films. The composition and structural morphology was confirmed by scanning electron microscopy (SEM), energy dispersive X-ray, and Raman spectroscopy. SEM imaging shows hexagonal plate crystallites growing perpendicular to the substrate, but these tend to align parallel to the surface when the quantity of reagent is reduced. The resistivity of the crystalline TiSe2 films is 3.36 ± 0.05 × 10–3 Ω·cm with a carrier density of 1 × 1022 cm–3. Very highly selective film growth from the reagent was observed onto photolithographically patterned substrates, with film growth strongly preferred onto the conducting TiN surfaces of SiO2/TiN patterned substrates. TiSe2 is selectively deposited within the smallest 2 μm diameter TiN holes of the patterned TiN/SiO2 substrates. The variation in crystallite size with different diameter holes is determined by microfocus X-ray diffraction and SEM, revealing that the dimensions increase with the hole size, but that the thickness of the crystals stops increasing above ∼20 μm hole size, whereas their lengths/widths continue to increase.

Journal Keywords: chemical vapor deposition; microfocus X-ray diffraction; Selective deposition; selenoether; single-source precursor; titanium selenide

Subject Areas: Chemistry, Physics, Technique Development


Instruments: I18-Microfocus Spectroscopy