Woo‐Hee Kim

Abstract 2D transition metal dichalcogenides (TMDs) have attracted much attention for their gas sensing applications due to their superior responsivity at typical room temperature. However, low power consumption and reliable selectivity are the two main requirements for gas sensors to be applicable in future electronic devices. Herein, a p‐type (WSe 2 /WS 2 ) and n‐type (MoS 2 /WSe 2 ) photovoltaic self‐powered gas sensor is demonstrated using 2D TMD heterostructures for the first time. The gas

Short-chain aminosilanes, namely, bis(N,N-dimethylamino)dimethylsilane (DMADMS) and (N,N-dimethylamino)trimethylsilane (DMATMS), have been used as Si precursors for atomic layer deposition (ALD) of SiO2. In this work, the DMADMS and DMATMS Si precursors are utilized as inhibitors for area-selective ALD (AS-ALD). The inhibitors selectively adsorb on a SiO2 surface but not on H–Si, so that SiO2 becomes selectively deactivated toward subsequent ALD. The deactivation of the SiO2 surface by the inhib

Area-selective atomic layer deposition (AS-ALD) is attracting increasing interest because of its ability to enable both continued dimensional scaling and accurate pattern placement for next-generation nanoelectronics. Here we report a strategy for depositing material onto three-dimensional (3D) nanostructures with topographic selectivity using an ALD process with the aid of an ultrathin hydrophobic surface layer. Using ion implantation of fluorocarbons (CFx), a hydrophobic interfacial layer is f

We fabricated metallic nanostructures directly on Si substrates through a hybrid nanoprocess combining atomic layer deposition (ALD) and a self-assembled anodic aluminum oxide (AAO) nanotemplate. ALD Ru films with Ru(DMPD)(EtCp) as a precursor and O(2) as a reactant exhibited high purity and low resistivity with negligible nucleation delay and low roughness. These good growth characteristics resulted in the excellent conformality for nanometer-scale vias and trenches. Additionally, AAO nanotempl

Ni thin films were deposited by atomic layer deposition (ALD) using bis(dimethylamino-2-methyl-2-butoxo)nickel [Ni(dmamb)(2)] as a precursor and NH3 gas as a reactant. The growth characteristics and film properties of ALD Ni were investigated. Low-resistivity films were deposited on Si and SiO2 substrates, producing high-purity Ni films with a small amount of oxygen and negligible amounts of nitrogen and carbon. Additionally, ALD Ni showed excellent conformality in nanoscale via holes. Utilizing

Abstract Area‐selective atomic layer deposition (AS‐ALD) offers tremendous advantages in comparison with conventional top‐down patterning processes that atomic‐level selective deposition can achieve in a bottom‐up fashion on pre‐defined areas in multi‐dimensional structures. In this work, a method for exploiting substrate‐dependent selectivity of aminosilane precursors for oxides versus nitrides through chemo‐selective adsorption is reported. For this purpose, AS‐ALD of SiO 2 thin films on SiO 2

Theoretical and experimental studies were performed on surface reactions during film growth and electrical properties of HfO₂ using two different Hf precursors, HfCl₄ and Hf(N(CH₃)₂)₄.

In this study, the growth characteristics and the film properties of Ru and RuO2 thin films were systematically investigated, focusing on the effects of the oxygen exposure and the growth temperature. Pure Ru thin films with low resistivity were deposited from bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)(2)] as a Ru precursor and oxygen (O-2) as a reactant by using thermal atomic layer deposition (ALD). Phase change from Ru to RuO2 was observed by controlling the growth parameters, including th

We carried out comprehensive studies on structural, optical, and electrical properties of aluminum-doped zinc oxide (AZO) films deposited by low pressure chemical vapor deposition (LP-CVD). The growth rates of LP-CVD AZO films increased slightly with Al doping. In addition, the resistivity was strongly dependent on the carrier electron concentration, also correlated with optical band gap and work function. All the AZO films exhibited high optical transmittance of >80% in the visible range of 400

We have systematically investigated the electronic structure of CeO2 dielectric by plasma enhanced atomic layer deposition (PE-ALD). The CeO2 films were deposited by using novel tris(isopropyl-cyclopentadienyl)cerium [Ce(iPrCp)3] precursor and O2 plasma. The energy band gap (3.48 eV), Fermi level (4.71 eV), and band offsets of PE-ALD CeO2 were elaborately determined by combining spectroscopic ellipsometry and ultraviolet photoemission spectroscopy (UPS) techniques. In addition, based on the expe

We report the influence of La substitution in epitaxial BiFeO3 thin films prepared by pulsed layer deposition on a Nb-doped SrTiO3 substrate, focusing on ferroelectric domain structure, leakage current, and multiferroic properties. Enhanced ferroelectric remanent polarization and reduced leakage current density were established via La substitution in the BiFeO3 film. Based on leakage conduction mechanism and piezoelectric force microscopy studies, this is indicative of reduced trap densities and

SiO2 is one of the most important dielectric materials that is widely used in the microelectronics industry, but its growth or deposition requires high thermal budgets. Herein, we report a low-temperature thermal atomic layer deposition (ALD) process to fabricate SiO2 thin films using a novel aminodisilane precursor with a Si–Si bond, 1,2-bis(diisopropylamino)disilane (BDIPADS), together with ozone. To compare the film quality, ALD SiO2 films grown at various temperatures from 250 down to 50 °C

CeO2 thin films were deposited by plasma-enhanced atomic layer deposition (PE-ALD). Novel Ce(iPrCp)3 [tris(isopropyl-cyclopentadienyl)cerium] was used as a Ce precursor, which showed clean evaporation with no residue and good thermal stability. For PE-ALD, O2 plasma was used as an oxidizing reactant. The PE-ALD process exhibited ALD mode with good self-saturation behavior and linear growth without any nucleation delay on Si substrate as a function of growth cycles. Additionally, it produced high