Plasma-Enhanced ALD of TiO₂ Using a Novel Cyclopentadienyl Alkylamido Precursor [Ti(Cp^Me)(NMe₂)₃] and O₂ Plasma

Abstract

Titanium oxide thin films of both amorphous and anatase morphologies have been deposited using remote plasma ALD over a wide temperature range (100-350 °C), using a novel heteroleptic alkylamido precursor Ti(Cp Me )(NMe 2 ) 3 . A high growth per cycle (GPC) of 0.07-0.08 nm (which is about 50 % higher than the GPC obtained with most other organometallic precursors) without any nucleation delay was observed. Rutherford backscattering (RBS) and X-ray photoelectron spectroscopy (XPS) studies on the deposited films revealed their stoichiometry and compositional purity: samples deposited at 100-350 °C had [O]/[Ti] ratios of ~2.0 ± 0.1. Samples deposited at 200 °C and above had C, H and N concentrations of less than 0.6, 2 and 2.3 at.%, respectively. Atomic force microscopy (AFM) and X-ray diffraction (XRD) studies revealed that films deposited at 300 °C and above had a significant crystalline (anatase) component, while films deposited at 100 and 200 °C were amorphous.

Plasma-assisted atomic layer deposition of TiO2 compact layers for flexible mesostructured perovskite solar cells

“…Between the two steps, the chamber was purged for 2 s with argon flow. The heteroleptic titanium precursor was chosen due to the higher growth per cycle (GPC) in comparison with other most common precursors, i.e., the homoleptic tetraisopropoxide (TTIP) (Potts et al, 2010;Sarkar et al, 2010). At 150 °C, the GPC of the process was 0.055 nm/cycle compared to 0.04 nm/cycle measured for the process with TTIP precursor.…”

Opportunities of Atomic Layer Deposition for Perovskite Solar Cells

“…The TiO 2 compact layers were deposited on conductive substrate (ITO-PET) at 150 o C in a thermal and remote plasma reactor (FlexAL TM ) using heteroleptic dimethylamido precursor with a methylcyclopentadienyl ligand (Ti(Cp Me )(NMe 2 ) 3 an O 2 inductively coupled plasma. Details and specifications of the ALD process have been extensively discussed in (22). A -plasma treatment (200W) of 3 min was performed prior to the ALD deposition.…”

Nitrogen-doping of bulk and nanotubular TiO2 photocatalysts by plasma-assisted atomic layer deposition

“…opto-electrical, crystallographic and mechanical) properties of the deposited layer [41][42][43] by tuning the composition of the gas feeding the plasma. Other parameters which contribute to control the properties of the layers are the plasma power, the plasma exposure time and the applied bias at the substrate where deposition occurs [44][45][46][47][48][49]. As an example, Profijt et al have shown that the crystal structure of TiO 2 can be tuned from anatase to rutile by varying the bias applied on the substrate holder [45].…”