The reaction mechanism of area-selective atomic layer deposition (AS-ALD) of AlO thin films using self-assembled monolayers (SAMs) was systematically investigated by theoretical and experimental studies. Trimethylaluminum (TMA) and HO were used as the precursor and oxidant, respectively, with octadecylphosphonic acid (ODPA) as an SAM to block AlO film formation. However, AlO layers began to form on the ODPA SAMs after several cycles, despite reports that CH-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 AlO film growth. Moreover, the amount of physisorbed TMA was affected by the partial pressure. By controlling it, we developed a new AS-ALD AlO process with high selectivity, which produces films of ∼60 nm thickness over 370 cycles. The successful deposition of AlO thin film patterns using this process is a breakthrough technique in the field of nanotechnology.

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A method for significantly increasing the growth rates (GRs) of high-k oxide thin films grown via plasmaenhanced atomic layer deposition (PE-ALD) by enhancing the plasma density through the addition of Ar gas to the O 2 plasma oxidant was developed. This approach led to improvements of ∼60% in the saturation GRs of PE-ALD ZrO 2 , HfO 2 , and SiO 2 . 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 O 2 plasma process. Optical emission spectroscopy analyses in conjunction with theoretical calculation of the electron energy distribution function revealed that adding Ar gas to the O 2 plasma increased the density of high-energy electrons, thereby generating more O 2 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. KEYWORDS: atomic layer deposition, O 2 /Ar plasma, oxide thin films, enhanced growth rates, high-energy electron temperature, increased plasma density

Metal-oxide-semiconductor (MOS) capacitors with an amorphous Ta 1Àx Zr x O composite gate dielectric film and a SiO 2 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 Ta 1Àx Zr x O/InP and Ta 1Àx Zr x O/SiO 2 /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 Ta 1Àx Zr x O alloy as a gate dielectric film for an InP substrate. XPS results showed that the Ta 1Àx Zr x O film retained its insulating characteristics and was thermally stable even after annealing at 500 1C. However, Fermi-level pinning and significant diffusion of indium through the Ta 1Àx Zr x O were observed. The diffusion of In was remarkably reduced after introducing the SiO 2 passivation layer, which resulted in an overall reduction in interfacial layer thickness. Parallel conductance contour measurements showed that the SiO 2 passivation layer resulted in unpinning of the Fermi-level. The introduction of a SiO 2 passivation layer with the Ta 1Àx Zr x O 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.