• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.91-91
• /
• 2012

We aim in synthesizing various functional thin films thinner than ~ 10 nm for environmental applications and photovoltaic devices. Atomic layer deposition is used for synthesizing inorganic thin films with a precise control of the film thickness. Several examples about application of our thin films for removing volatile organic compounds (VOC) will be highlighted, which are summarized in the below. 1) $TiO_2$ thin films prepared by ALD at low temperature ($<100^{\circ}C$) show high adsorption capacity for toluene. In combination with nanostructured templates, $TiO_2$ thin films can be used as building-block of high-performing VOC filter. 2) $TiO_2$ thin films on carbon fibers and nanodiamonds annealed at high temperatures are active for photocatalytic oxidation of VOCs, i.e. photocatalytic filter can be created by atomic layer deposition. 3) NiO can catalyze oxidation of toluene to $CO_2$ and $H_2O$ at $<300^{\circ}C$. $TiO_2$ thin films on NiO can reduce poisoning of NiO surfaces by reaction intermediates below $200^{\circ}C$. We also fabricated inverted organic solar cell based on ZnO electron collecting layers on ITO. $TiO_2$ thin films with a mean diameter less than 3 nm on ZnO can enhance photovoltaic performance by reducing electron-hole recombination on ZnO surfaces.

• Korean Journal of Materials Research
• /
• v.13 no.9
• /
• pp.606-612
• /
• 2003

Surface and mechanical properties of thin films with submicron thickness was characterized by nanoindentation with Berkovich and Vickers tips, and scanning probe microscopy. Nanoindention was made in a depth range of 15 to 200 nm from the surface by applying tiny force in a range from 150 to $9,000 \mu$N. Stiffness, contact area, hardness, and elastic modulus were determined from the force-displacement curve obtained. Reliability was first tested by using fused quartz, a standard sample. Elastic modulus and hardness values of fused quartz measured were the same as those reported in the literature within two percent of error. Mechanical properties of ITO thin film were characterized in a depth range of 15∼200nm. As indentation depth increased, elastic modulus and hardness decreased by substrate effect. Ion beam deposited DLC thin films were indented in a depth range of 40∼50 nm. The results showed that the DLC thin film using benzene and bias voltage 0∼-50 V has elastic modulus and hardness value of 132 and 18 GPa respectively. Pure DLC thin films showed roughnesses lower than 0.25 nm, but silicon-added DLC thin films showed much higher roughness values, and the wavy surface morphology.

• Journal of the Korean Society for Heat Treatment
• /
• v.13 no.2
• /
• pp.91-97
• /
• 2000

The structure and mechanical properties of TiN and TiCN thin films deposited on STD61 steel substrates by the RF-sputtering methods has been studied by using XPS, XRD, micro-hardness tester, scratch tester, and wear-resistance tester. XPS results showed that the TiCN thin film formed with chemical bonding state. The TiN thin films grew with (111) orientation having the lowest strain energy by compressive stress, whereas the TiCN thin films grew with both (111) and (200) orientation, but (200) orientation having the lowest surface energy becomes dominant as carbon contents increase. The pre-etching treatment of substrate did not affect on the preferred orientation of thin films, but it played an important role in improving mechanical properties of thin films such as the hardness, adhesion and wear- resistance. Especially, the TiCN thin films showed the superior wear resistances due to high hardness and low friction coefficient compared with TiN thin films.

• Journal of the Semiconductor & Display Technology
• /
• v.19 no.3
• /
• pp.100-105
• /
• 2020

Recently, as display and semiconductor devices have been miniaturized and highly integrated, there is a demand for optimization of the structural characteristics of the thin film accordingly. The sputtering device has the advantage of stably obtaining a desired thin film depending on the material selected for the target. However, due to the structural characteristics of the sputtering equipment, the structural characteristics of the film may be different depending on the incidence angle of the sputtering target material to the substrate. In this study, the characteristics of the thin film material according to the scattering angle of the target material and the incidence position of the substrate were studied to find the optimization design rule of the sputtering equipment. To this end, a Si thin film of 1 ㎛ or less was deposited on the Si(100) substrate, and then the microstructure, reflectance, surface roughness, and thin film crystallinity of the thin film formed for each substrate location were investigated. As a result of the study, it was found that as the sputter scattering angle increased and the substrate incident angle decreased, the gap energy along with the surface structure of the thin film increased from 1.47 eV to 1.63 eV, gradually changing to a non-conductive tendency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2001.11a
• /
• pp.455-458
• /
• 2001

The thin films of high permitivity in ferroelectric materials using a capacitor are applied to DRAMs and FRAMs. (Ba, Sr)TiO$_3$ thin films as ferroelectric materials were prepared by the sol-gel method and made by spin-coating on the Pt/Ti/SiO$_2$/Si substrate at 4,700 [rpm] for 10 seconds. The devices of BST thin films to composite (Ba$\_$0.7/Sr$\_$0.3/)TiO$_3$ were fabricated by changing of the depositing layer number on Pt/Ti/SiO$_2$/Si substrate. The thin film capacitor to be ferroelectric devices was investigated by structural and electrical properties. The thickness of BST thin films at each coating numbers 3, 4 and 5 times was 2500[${\AA}$], 3500[${\AA}$], 3800[${\AA}$]. The dielectric factor of thin film when the coating numbers were 3, 4 and 5 times was 190, 400 and 460 on frequency 1[MHz]. The dielectric loss of BST thin film was linearly increased by increasing of the specimen area.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.05c
• /
• pp.190-193
• /
• 2003

Sm-doped lead zirconate titanate($Pb_{1.1}(Zr_{0.6}Ti_{0.4})O_3$; PZT) thin films on the Pt(111)/Ti/$SiO_2$/Si(100) substrates prepared by a sol-gel method. The effect on structural and electrical properties of PZT thin films measured according to the Sm content. Sm-doping altered significantly dielectric and ferroelectric properties. The remanent polarization and the coercive field decreased with the increasing Sm content. The dielectric constant and the dielectric loss of PZT thin films decreased with the increasing Sm content. At 100 kHz, the dielectric constant and the dielectric loss of. the 0.3 mol% of Sm-doped PZT thin film were 1200 and 0.12 respectively. The remanent polarization (2Pr) of the 0.3 mol% of Sm-doped PZT thin film was $52.13{\mu}C/cm^2$ and the coercive field was 94.01 kV/cm. The 0.3 mol% of Sm-doped PZT thin film showed an improved fatigue characteristic comparing to the undoped PZT thin film.

• Textile Coloration and Finishing
• /
• v.16 no.5
• /
• pp.42-47
• /
• 2004

The main objective of this work is to develop melt-blown nonwoven fabric composite materials have electromagnetic shielding characteristics using thin copper film. Melt-blown nonwoven fabric is the matrix phase and thin copper films are the reinforcement of the composite materials. Thin copper films are incorporated as conductive fillers to provide the electromagnetic shielding property of the melt-blown nonwoven fabric. The width and interval of thin copper films in the nonwoven fabric are varied by changing 1, 3, 5 mm for thin copper film's width and 1, 3, 5 mm for thin copper film's interval. The shielding effectiveness(SE) of various melt-blown nonwoven fabrics is measured in the frequency range of 50 MHz to 1.8 GHz. The variations of SE of melt-blown nonwoven fabric with width and interval of thin copper films are described. Suitability of melt-blown nonwoven fabric for electromagnetic shielding applications is discussed. The results indicate that the melt-blown nonwoven fabric composite material using thin copper film can be used for the purpose of electromagnetic shielding.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.07a
• /
• pp.885-888
• /
• 2000

The effects of deposition temperature and post annealing process of ferroelectric PbZr$\sub$0.52/Ti$\sub$0.48/O$_3$(PZT) thin films by pulsed laser deposition (PLD) were investigated. The PZT thin films were deposited at 400, 450, 500, and 550$^{\circ}C$, with/without post annealing at 650$^{\circ}C$ for 30 min. The PZT thin films deposited above 500$^{\circ}C$ without post annealing were crystallized into peroveskite phase, but the PZT thin films deposited below 450$^{\circ}C$ had pyrochlore phase. The PZT thin films deposited below 450$^{\circ}C$ with post annealing also crystallized into pure perovskite. Compared to the PZT thin films which were deposited at 450$^{\circ}C$ and post annealed, the films deposited at 550$^{\circ}C$ have a columnar microstructure and high remnant polarization 28 (${\mu}$C/cm$^2$). With in-situ annealing at oxygen ambient, the PZT thin films reduced oxygen vacancies and increased retained polarization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.51-54
• /
• 2003

Tb-doped lead zirconate titanate($Pb_{1.1}(Zr_{0.6}Ti_{0.4})O_3$; PZT) thin films on $Pt(111)/Ti/SiO_2/Si(100)$ substrates prepared by a sol-gel method. Films have a Zr/Ti ratio of 60:40 and perovskite phase structure. The effect on the structural and electrical properties of films measured according to Tb content. Dielectric and ferroelectric properties of PZT thin films were altered significantly by Tb-doping. The PZT thin film with higher dielectric constant and improved leakage current characteristic was obtained by adding 0.3 mol% Tb. At 100 kHz, the dielectric constant and the dielectric loss of the 0.3 mol% Tb-doped PZT thin film were 1611 and 0.24, respectively The remanent polarization(2Pr) of the 0.3 mol% Tb-doped PZT thin film was $61.4\;{\mu}C/cm^2$ and the coercive field was 61.9 kV/cm. Tb-doped PZT thin films showed improved fatigue characteristics comparing to the undoped PZT thin film.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.08a
• /
• pp.207.2-207.2
• /
• 2013

Oxide-based thin film transistors have been attempted as powerful candidates for driving circuits for active-matrix organic light-emitting diodes and transparent electronics. The oxide TFTs are based on the amorphous multi-component oxides involving zinc, indium, and/or tin elements as main cation sources. The current work employed RF sputtering in order to deposit zinc-tin oxide thin films applicable to transparent oxide thin film transistors. The deposited thin film was characterized and probed in terms of materials and devices. The physical/chemical characterizations were performed using X-ray diffraction, Atomic Force Microscopy, Spectroscopic Ellipsometry, and X-ray Photoelectron Spectroscopy. The thin film transistors were fabricated using a bottom-gated structure where thermally-grown silicon oxide layers were applied as gate-dielectric materials. The inherent properties of oxide thin films are combined with the corresponding device performances with the aim to fabricating the multi-component oxide thin films being optimized towards transparent electronics.