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In the present study, SiO2 was deposited using the atomic layer deposition (ALD) with a 1,2-bis(diisopropylamino)disilane (BDIPADS) precursor. The use of this precursor exhibited a higher growth rate and lower initial growth temperature than the use of diisopropylaminosilane (DIPAS) did. The ALD reaction using BDIPADS produced SiO2 with excellent quality owing to the self-catalytic reaction between the amine ligand and O3; therefore, the SiO2 film has no impurities. When the growth temperature was increased gradually, the stoichiometry and density of SiO2 were improved also because the reaction between surface adsorbate species was nearly complete. ALD SiO2 exhibited a higher dielectric constant than the bulk SiO2 did, from the metal-oxide-semiconductor capacitor, because of the incorporated hydroxyl groups in the film. Furthermore, the etching characteristics were modulated by changing the growth temperature to ensure that the film can be used as a hard mask for lithography. From the DFT calculation, high reaction energy between the BDIPADS and Si–OH was observed. Moreover, the Si–Si cleavage results in the existence additional reaction sites, such as amine group, allowing low-temperature growth and enhanced productivity. Therefore, the number of Si atoms in a molecule affects the growth rate and initial growth temperature to ensure that BDIPADS is a highly excellent precursor for the SiO2 deposition; therefore, its use can lead to a remarkably high productivity.

A method for significantly increasing the growth rates (GRs) of high- k oxide thin films grown via plasma-enhanced atomic layer deposition (PE-ALD) by enhancing the plasma density through the addition of Ar gas to the O2 plasma oxidant was developed. This approach led to improvements of ∼60% in the saturation GRs of PE-ALD ZrO2, HfO2, and SiO2. Furthermore, despite the significantly higher GR enabled by PE-ALD, the mechanical and dielectric properties of the PE-ALD oxide films were similar or even superior to those of films grown via the conventional O2 plasma process. Optical emission spectroscopy analyses in conjunction with theoretical calculation of the electron energy distribution function revealed that adding Ar gas to the O2 plasma increased the density of high-energy electrons, thereby generating more O2 plasma species, such as ions and radicals, which played a key role in improving the GRs and the properties of the films. This promising approach is expected to facilitate the high-volume manufacturing of films via PE-ALD, especially for use as gate insulators in thin-film transistor-based devices in the display industry.

We have investigated the atomic layer deposition (ALD) of GeO2 thin films that dissolve in water rapidly and have excellent electrical properties for use in memory devices. The growth characteristics based on surface reactions during the ALD process are discussed by correlation with experimental results and atomistic theoretical calculation. Compared to sputtered GeO2 films, the ALD-grown GeO2 is perfect, pure, and water-soluble at room temperature and has better electrical properties for use as the dielectric layer in memory devices. The superior film properties of ALD GeO2 are attributed to the higher film density, high purity, low roughness, and highly stoichiometric film composition. Finally, we demonstrate the fabrication of charge-trapping memory (CTM) devices with ALD GeO2, and that the electrical information stored in the CTM can be eliminated immediately by exposure to one droplet of water at room temperature. Thus, ALD GeO2 could find widespread application in the fabrication of secure memory de...

The reaction mechanism of area-selective atomic layer deposition (AS-ALD) of Al2O3 thin films using self-assembled monolayers (SAMs) was systematically investigated by theoretical and experimental studies. Trimethylaluminum (TMA) and H2O were used as the precursor and oxidant, respectively, with octadecylphosphonic acid (ODPA) as an SAM to block Al2O3 film formation. However, Al2O3 layers began to form on the ODPA SAMs after several cycles, despite reports that CH3-terminated SAMs cannot react with TMA. We showed that TMA does not react chemically with the SAM but is physically adsorbed, acting as a nucleation site for Al2O3 film growth. Moreover, the amount of physisorbed TMA was affected by the partial pressure. By controlling it, we developed a new AS-ALD Al2O3 process with high selectivity, which produces films of ∼60 nm thickness over 370 cycles. The successful deposition of Al2O3 thin film patterns using this process is a breakthrough technique in the field of nanotechnology

This paper investigates the impact of an atomic layer-deposited Y2O3 dielectric on the passivation of a GeO2 layer in GeO2-based Ge gate stacks. The equivalent oxide thickness scalability and thermal stability of the ultrathin Y2O3 layer are evaluated at different Y2O3 thicknesses and annealing conditions in detail. Experimental results show that a Y2O3 layer thickness of 1.0 nm is required to serve as a GeO2 passivation layer while retaining gate-stack performance at 400 °C postdeposition annealing. However, at a higher annealing temperature of 500 °C, the barrier property deteriorates and allows GeO desorption. The proposed gate-stack implies the applicability of a Y2O3 passivation method for further scaled GeO2-based Ge gate stacks.

Although plasma-enhanced atomic layer deposition (PE-ALD) results in several benefits in the formation of high-k dielectrics, including a low processing temperature and improved film properties compared to conventional thermal ALD, energetic radicals and ions in the plasma cause damage to layer stacks, leading to the deterioration of electrical properties. In this study, the growth characteristics and film properties of PE-ALD Al2O3 were investigated using a very-high-frequency (VHF) plasma reactant. Because VHF plasma features a lower electron temperature and higher plasma density than conventional radio frequency (RF) plasma, it has a larger number of less energetic reaction species, such as radicals and ions. VHF PE-ALD Al2O3 shows superior physical and electrical properties over RF PE-ALD Al2O3, including high growth per cycle, excellent conformality, low roughness, high dielectric constant, low leakage current, and low interface trap density. In addition, interlayer-free Al2O3 on Si was achieved in VHF PE-ALD via a significant reduction in plasma damage. VHF PE-ALD will be an essential process to realize nanoscale devices that require precise control of interfaces and electrical properties.

We developed an Al sputtering process by varying the plasma power, process temperature, and film thickness. We observed an increase of hillock distribution and average diameter with increasing plasma power, process temperature, and film thickness. Since the roughness of a film increases with the increase of the distribution and average size of hillocks, the control of hillock formation is a key factor in the reduction of Al corrosion. We observed the lowest hillock formation at 30 W and 100 oC. This growth characteristic of sputtered Al thin films will be useful for the reduction of Al corrosion in the future of the electronic packaging field.

A method for significantly increasing the growth rates (GRs) of high- k oxide thin films grown via plasma-enhanced atomic layer deposition (PE-ALD) by enhancing the plasma density through the addition of Ar gas to the O

Metal–oxide-semiconductor (MOS) capacitors with an amorphous Ta1−xZrxO composite gate dielectric film and a SiO2 passivation layer were fabricated on an indium phosphide (InP) substrate. To investigate the impact of the passivation layer, the interfacial chemical, physical and electrical properties of the Ta1−xZrxO/InP and Ta1−xZrxO/SiO2/InP MOS structures were studied in detail. Electrical conductivity measurements combined with chemical bonding analysis using X-ray photoelectron spectroscopy (XPS) and electron dispersive spectroscopy (EDS) were conducted in order to evaluate the suitability of a Ta1−xZrxO alloy as a gate dielectric film for an InP substrate. XPS results showed that the Ta1−xZrxO film retained its insulating characteristics and was thermally stable even after annealing at 500 °C. However, Fermi-level pinning and significant diffusion of indium through the Ta1−xZrxO were observed. The diffusion of In was remarkably reduced after introducing the SiO2 passivation layer, which resulted in an overall reduction in interfacial layer thickness. Parallel conductance contour measurements showed that the SiO2 passivation layer resulted in unpinning of the Fermi-level. The introduction of a SiO2 passivation layer with the Ta1−xZrxO composite gate dielectric film was found to provide remarkably improved dielectric performance, which was mainly attributed to reduced In diffusion and the passivation of interfacial and bulk dielectric defects.

The reaction mechanism of area-selective atomic layer deposition (AS-ALD) of Al