Thermal Annealing of Molecular Layer-Deposited Indicone Toward Area-Selective Atomic Layer Deposition

Abstract

Area-selective atomic layer deposition (AS-ALD) is a promising technique for fine nanoscale patterning, which may overcome the drawbacks of conventional top-down approaches for the fabrication of future electronic devices. However, conventional materials and processes often employed for AS-ALD are inadequate for conformal and rapid processing. We introduce a new strategy for AS-ALD based on molecular layer deposition (MLD) that is compatible with large-scale manufacturing. Conformal thin films of "indicone" (indium alkoxide polymer) are fabricated by MLD using INCA-1 (bis(trimethylsily)amidodiethylindium) and HQ (hydroquinone). Then, the MLD indicone films are annealed by a thermal heat treatment under vacuum. The properties of the indicone thin films with different annealing temperatures were measured with multiple optical, physical, and chemical techniques. Interestingly, a nearly complete removal of indium from the film was observed upon annealing to ca. 450 °C and above. The chemical mechanism of the thermal transformation of the indicone film was investigated by density functional theory calculations. Then, the annealed indicone thin films were applied as an inhibiting layer for the subsequent ALD of ZnO, where the deposition of approximately 20 ALD cycles (equivalent to a thickness of approximately 4 nm) of ZnO was successfully inhibited. Finally, patterns of annealed MLD indicone/Si substrates were created on which the area-selective deposition of ZnO was demonstrated.

Facile synthesis of an organic/inorganic hybrid 2D structure tincone film by molecular layer deposition

“…46 A previous study of aromatic-based metalcones confirmed that graphitization occurs, through the investigation of D and G peaks by pyrolysis in the vacuum annealing process at around 450 °C. 31 In MLD tincone films, the peak corresponding to the position of the D peak could not be investigated in this study before and after the annealing process, although in the benzene ring, the C-H bending and the stretching vibration peak could be confirmed at 1230 cm −1 and 1260 cm −1 , respectively. The absence of a D peak indicated that graphitization of the benzene ring through the annealing process did not occur and the aromatic ring was maintained in the film.…”

“…29 In previous research, alucone and indicone thin films, deposited using trimethylaluminum (TMA) and bis (trimethylsily) amidodiethyl indium (INCA-1) with HQ, was rearranged into a graphitic carbon structure by pyrolysis after thermal annealing. 30,31 As the metal-organic bond was broken during the annealing process, an unstable energy state was activated and crystalline graphitic carbon could be fabricated relatively easily using an aromatic ring-based organic molecule. As described in the following, an organic/inorganic polymer-based film produced by MLD could be readily rearranged into a graphitic structure through the post-processing process.…”

Effects of Al Precursors on the Characteristics of Indium–Aluminum Oxide Semiconductor Grown by Plasma-Enhanced Atomic Layer Deposition

“…Δ G values have been thermodynamically favorable for the reaction between TMA and In 2 O 3 (In 2 O 3 + 2Al­(CH 3 ) 3 (g) = Al 2 O 3 + 2In­(CH 3 ) 3 (g), Δ G = −317.89 kcal) . It has also been reported that In component from organic−inorganic hybrid indicone films can be removed by vacuum annealing, since the In−O binding energy is relatively weak . In summary, TMA would accelerate the etching reaction of In from the substrate because of the small precursor size and high reactivity in the ALD multicomponent deposition.…”

“…30 It has also been reported that In component from organic−inorganic hybrid indicone films can be removed by vacuum annealing, since the In−O binding energy is relatively weak. 41 In summary, TMA would accelerate the etching reaction of In from the substrate because of the small precursor size and high reactivity in the ALD multicomponent deposition. As a result, a multistep IAO thin film using TMA had formed an insulating film, and hence was not suitable for application as a TFT channel material of TFT.…”

Atomic/Molecular Layer Deposition for Designer's Functional Metal–Organic Materials

“…In the few additional studies involving the 4d or 5d transition metals, Nb‐based films have been deposited from Nb(OEt) 5 in combination with HQ, [ 421 ] Mo‐based films from molybdenum hexacarbonyl together with 1,2‐ethanedithiol (EDT), [ 242,243 ] 1,4‐butanedithiol, and BDT, [ 243 ] and In‐based films from bis(trimethylsilyl)amidodiethylindium (INCA‐1) and HQ. [ 369,422,423 ] The as‐deposited In–HQ films showed a structural change upon exposure to ambient air and were found promising as flexible transparent films. [ 424 ] Tin‐based hybrid films have been deposited from Sn–TDMA together with GL, [ 220,425 ] and EG, [ 220 ] and also from HS–Sn with HQ.…”