Area Selective Growth of Titanium Diselenide Thin Films into Micropatterned Substrates by Low-Pressure Chemical Vapor Deposition.
The neutral, distorted octahedral complex [TiCl4(SenBu2)2] (1), prepared from the reaction of TiCl4with the neutral SenBu2in 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 SiO2and 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 TiSe2films is 3.36 ± 0.05 × 10-3Ω·cm with a carrier density of 1 × 1022cm-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. TiSe2is selectively deposited within the smallest 2 μm diameter TiN holes of the patterned TiN/SiO2substrates. 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.
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
Sophie L
SL
Benjamin
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
C H Kees
CH
de Groot
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
Chitra
C
Gurnani
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
Andrew L
AL
Hector
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
Ruomeng
R
Huang
Diamond Light Source Ltd., Didcot, OX11 0DE, United Kingdom.
Konstantin
K
Ignatyev
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
William
W
Levason
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
Stuart J
SJ
Pearce
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
Fiona
F
Thomas
Chemistry and Electronics and Computer Science, University of Southampton , Southampton, SO17 1BJ, United Kingdom.
Gillian
G
Reid
Selective deposition; chemical vapor deposition; microfocus X-ray diffraction; selenoether; single-source precursor; titanium selenide