김형식 교수

Microstructural evolution and resulting changes in electrical properties of atomic-layerdeposition-grown HfO2 on SiO2/Si substrates were studied as a function of annealing temperature in a N2 ambient. As deposited ∼30-Å-thick HfO2 on 15 and 25 Å thermal SiO2 were almost entirely amorphous, although a low density of crystalline seeds were observed and crystallization occurred from these nuclei during furnace anneals at temperatures >∼500 °C. The major crystalline phase thus formed was mono

High-k metal oxide gate dielectrics may be required to extend Moore’s law of semiconductor device density scaling into the future. However, growth of a thin SiO2-containing interface layer is almost unavoidable during the deposition of metal oxide films onto Si substrates. This limits the scaling benefits of incorporating high-k dielectrics in future transistors. A promising approach, in which oxygen-gettering metal overlayers are used to engineer the thickness of the SiO2-based interface layer

High-k dielectric deposition processes for gate dielectric preparation on Si surfaces usually result in the unavoidable and uncontrolled formation of a thin interfacial oxide layer. Atomic layer deposition of ∼55-Å ZrO2 film on a Ge (100) substrate using ZrCl4 and H2O at 300 °C was found to produce local epitaxial growth [(001) Ge//(001) ZrO2 and [100] Ge//[100] ZrO2] without a distinct interfacial layer, unlike the situation observed when ZrO2 is deposited using the same method on Si. Relativel

The microstructural and electrical properties of Ge-based metal–oxide–semiconductor capacitors containing high-k gate dielectric layers were investigated with and without the presence of a GeOxNy interface layer. The effect of this nitrided layer on thermal stability of the metal oxide/Ge structures was probed by medium energy ion energy spectroscopy (MEIS). Atomic-layer deposited HfO2 on a chemical oxide-terminated Ge (100) surface exhibited poor capacitance–voltage behavior; however, direct su

The wafer-scale synthesis of two-dimensional molybdenum disulfide (MoS2) films, with high layer-controllability and uniformity, remains a significant challenge in the fields of nano and optoelectronics. Here, we report the highly thickness controllable growth of uniform MoS2 thin films on the wafer-scale via a spin-coating route. Formulation of a dimethylformamide-based MoS2 precursor solution mixed with additional amine- and amino alcohol-based solvents (n-butylamine and 2-aminoethanol) allowed

The crystallization kinetics of ∼3 nm HfO2 films grown by atomic layer deposition (ALD) on SiO2-passivated Si (100) wafers were investigated using an in situ transmission electron microscope (TEM) with heating capability. Through gray-scale analysis of dark-field TEM images, it was found that a two-dimensional nucleation and growth mechanism with a decreasing of nucleation rate could account for the observed transformation rate behavior. The effects of crystalline defects (e.g., grain boundaries

We investigated, for the first time, the photoresponse characteristics of solution-synthesized MoS2 phototransistors. The photoresponse of the solution-synthesized MoS2 phototransistor was solely determined by the interactions of the photogenerated charge carriers with the surface adsorbates and the interface trap sites. Instead of contributing to the photocurrent, the illumination-generated electron-hole pairs were captured in the trap sites (surface and interface sites) due to the low carrier

We explore a novel patterning method for flexible and transparent Ag nanowire electrodes using oxygen plasma treatment without a toxic etchant and its application to source/drain electrodes of MoS₂-based thin-film transistors.

Nanostructured Ag thin films solution-deposited on glass and plastic substrates are patterned by direct exposure to a pulsed Nd:YAG laser without using a photoresist layer. Sharp-edged patterns with a feature size scaled down to ca. 2 µm are obtainable.