1 research outputs found
Cycloheptatrienyl-Cyclopentadienyl Heteroleptic Precursors for Atomic Layer Deposition of Group 4 Oxide Thin Films
Atomic layer deposition (ALD) processes for the growth
of ZrO<sub>2</sub> and TiO<sub>2</sub> were developed using novel
precursors.
The novel processes were based on cycloheptatrienyl (CHT, -C<sub>7</sub>H<sub>7</sub>) – cyclopentadienyl (Cp, -C<sub>5</sub>H<sub>5</sub>) compounds of Zr and Ti, offering improved thermal stability
and purity of the deposited oxide films. The Cp<sup>Me</sup>ZrCHT/O<sub>3</sub> ALD process yielded high growth rate (0.7–0.8 Å/cycle)
over a wide growth temperature range (300–450 °C) and
diminutive impurity levels in the deposited polycrystalline films.
Growth temperatures exceeding 400 °C caused partial decomposition
of the precursor. Low capacitance equivalent thickness (0.8 nm) with
low leakage current density was achieved. In the case of Ti, the novel
precursor, namely CpTiCHT, together with ozone as the oxygen source
yielded films with low impurity levels and a strong tendency to form
the desired rutile phase upon annealing at rather low temperatures.
In addition, the thermal stability of the CpTiCHT precursor is higher
compared to the usually applied ALD precursors of Ti. The introduction
of this new ALD precursor family offers a basis for further improving
the ALD processes of group 4 oxide containing thin films for a wide
range of applications