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Indium oxide is currently in the spotlight of the micro-optoelectronics industry because of its high carrier concentration, electrical conductivity, and transmittance in the visible-light region. Among the methods of depositing indium oxide, atomic layer deposition (ALD) has the advantage of thickness control and conformality. In addition, it has high conformality, but a slow deposition rate. Therefore, plasma-enhanced ALD, which uses highly reactive radicals, is receiving attention. ALD is based on a self-limiting reaction. Therefore, the selection of the precursor is important because the ligand that reacts with the surface has a significant influence on the reaction. Herein, DIP-3 and DIP-4, amine/alkyl-based precursors, were developed based on previously used precursors. The growth characteristics of indium oxide deposited through the O2 plasma-enhanced ALD process using these two precursors differed depending on the precursor used. Alkyl-based DIP-4 resulted in a higher growth rate (∼1 Å per cycle) compared to that of amine-based DIP-3. The difference in the properties is related to the new ligands of the two precursors. DIP-4 was stably adsorbed on the surface with an energy reduction of 173 kJ mol−1, which is greater than that of DIP-3. Owing to its small size and added ligand, DIP-4 covered the substrate surface quickly and accelerated the film growth. The consumption of more hydroxyl groups can lead to the formation of more nuclei, and the coarsening of the crystals based on this phenomenon is associated with an increase in the growth per cycle (GPC). [ABSTRACT FROM AUTHOR]

Organic light emitting diodes (OLEDs) and amorphous oxide semiconductors (AOSs), which are very important technologies in high performance flexible displays, have issues related to degradation due to diffusion of water and hydrogen, respectively. To solve these issues, gas diffusion barrier properties were evaluated with aluminum oxide deposited by atomic layer deposition (ALD) and alucone deposited by molecular layer deposition (MLD) using trimethylaluminum (TMA) as a metal precursor and H2O and hydroquinone (HQ) as co-reactants, respectively. The water vapor transmission rate (WVTR) and hydrogen gas permeability (HGP) were measured for the fabricated films via electrical calcium tests and vacuum time-lag, respectively. To enhance the diffusion barrier properties, Al2O3/alucone hybrid multi-layer structures were successfully deposited through an in situ ALD/MLD process. The 4.5 dyads of the Al2O3/alucone structure showed improved barrier properties compared to the single Al2O3 film with a WVTR of 8.24 × 10−5 g m−2 day−1 and a HGP of 9.93 × 10−5 barrer, and factors related to gas diffusion in multi-layer structures were discussed. The stability to external stress was also evaluated based on the WVTR change rate after the bending test, and we confirmed that the stability of the multi-layer structures was improved due to the flexibility of inserted alucone layers. All the developed structures had a high optical transmittance of >80% in the 300–800 nm wavelength region based on UV-vis measurements. [ABSTRACT FROM AUTHOR]

Low-k SiONC thin films with excellent thermal stabilities were deposited using plasma-assisted molecular layer deposition (PA-MLD) with a tetraisocyanatesilane (Si(NCO) 4 ) precursor, N 2 plasma, and phloroglucinol (C 6 H 3 (OH) 3 ). By adjusting the order of the N 2 plasma exposure steps within the PA-MLD process, we successfully developed a deposition technique that allows accurate control of thickness at the Ångström level via self-limiting reactions. The thicknesses of the thin films were measured through spectroscopic ellipsometry (SE). By tuning the N 2 plasma power, we facilitated the formation of -NH 2 sites for phloroglucinol adsorption, achieving a growth per cycle of 0.18 Å cycle -1 with 300 W of N 2 plasma power. Consequently, the thickness of the films increased linearly with each additional cycle. Moreover, the organic linkers within the film formed stable bonds through surface reactions, resulting in a negligible decrease in thickness of approximately -11% even upon exposure to a high annealing temperature of 600 °C. This observation was confirmed by SE, distinguishing the as-prepared film from previously reported low-k films that fail to maintain their thickness under similar conditions. X-ray photoelectron spectroscopy (XPS) and current-voltage (I-V) and capacitance-voltage (C-V) measurement were conducted to evaluate the composition, insulating properties, and dielectric constant according to the deposition and annealing conditions. XPS results revealed that as the plasma power increased from 200 to 300 W, the C/Si ratio increased from 0.37 to 0.67, decreasing the dielectric constant from 3.46 to 3.12. Furthermore, there was no significant difference in the composition before and after annealing, and the hysteresis decreased from 0.58 to 0.19 V owing to defect healing, while maintaining the leakage current density, breakdown field, and dielectric constant. The low dielectric constant, accurate thickness control, and excellent thermal stability of this MLD SiONC thin film enable its application as an interlayer dielectric in back-end-of-line process., (© 2024 IOP Publishing Ltd.)

Organic light emitting diodes (OLEDs) and amorphous oxide semiconductors (AOSs), which are very important technologies in high performance flexible displays, have issues related to degradation due to diffusion of water and hydrogen, respectively. To solve these issues, gas diffusion barrier properties were evaluated with aluminum oxide deposited by atomic layer deposition (ALD) and alucone deposited by molecular layer deposition (MLD) using trimethylaluminum (TMA) as a metal precursor and H 2 O and hydroquinone (HQ) as co-reactants, respectively. The water vapor transmission rate (WVTR) and hydrogen gas permeability (HGP) were measured for the fabricated films via electrical calcium tests and vacuum time-lag, respectively. To enhance the diffusion barrier properties, Al 2 O 3 /alucone hybrid multi-layer structures were successfully deposited through an in situ ALD/MLD process. The 4.5 dyads of the Al 2 O 3 /alucone structure showed improved barrier properties compared to the single Al 2 O 3 film with a WVTR of 8.24 × 10 -5 g m -2 day -1 and a HGP of 9.93 × 10 -5 barrer, and factors related to gas diffusion in multi-layer structures were discussed. The stability to external stress was also evaluated based on the WVTR change rate after the bending test, and we confirmed that the stability of the multi-layer structures was improved due to the flexibility of inserted alucone layers. All the developed structures had a high optical transmittance of >80% in the 300-800 nm wavelength region based on UV-vis measurements.

High-density SnO x and SiO x thin films were deposited via atomic layer deposition (ALD) at low temperatures (100 °C) using tetrakis(dimethylamino)tin(IV) (TDMASn) and di-isopropylaminosilane (DIPAS) as precursors and hydrogen peroxide (H 2 O 2 ) and O 2 plasma as reactants, respectively. The thin-film encapsulation (TFE) properties of SnO x and SiO x were demonstrated with thickness dependence measurements of the water vapor transmission rate (WVTR) evaluated at 50 °C and 90% relative humidity, and different TFE performance tendencies were observed between thermal and plasma ALD SnO x . The film density, crystallinity, and pinholes formed in the SnO x film appeared to be closely related to the diffusion barrier properties of the film. Based on the above results, a nanolaminate (NL) structure consisting of SiO x and SnO x deposited using plasma-enhanced ALD was measured using WVTR (H 2 O molecule diffusion) at 2.43 × 10 -5 g/m 2 day with a 10/10 nm NL structure and time-lag gas permeation measurement (H 2 gas diffusion) for applications as passivation layers in various electronic devices.