• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.52 no.1
• /
• pp.6-11
• /
• 2003

The multi layer spiral inductors, which enhance the quality factor Q of an inductor fabricated on the silicon substrate, has been designed using a TSMC CMOS 0.2sum 1-poly 5-metal layer technology. To investigate the performance of the designed inductors, a 2.5-dimensional field simulation tool(Momentum) is used. The simulation results show that the quality factor Q of the 5-metal inductor is improved 1.8 times over that of a convention31 spiral inductor at 2GHz for wireless LAN applications.

• Journal of the Microelectronics and Packaging Society
• /
• v.21 no.3
• /
• pp.67-71
• /
• 2014

An attempt to grow high quality GaN on silicon substrate using metal organic chemical vapor deposition (MOCVD), herein GaN epitaxial layers were grown on various Si(111) substrates. Thin Platinum layer was deposited on Si(111) substrate using sputtering, followed by thermal annealing to form Pt nano-clusters which act as masking layer during dry-etched with inductively coupled plasma-reactive ion etching to generate nano-patterned Si(111) substrate. In addition, micro-patterned Si(111) substrate with circle shape was also fabricated by using conventional photo-lithography technique. GaN epitaxial layers were subsequently grown on micro-, nano-patterned and conventional Si (111) substrate under identical growth conditions for comparison. The GaN layer grown on nano-patterned Si (111) substrate shows the lowest crack density with mirror-like surface morphology. The FWHM values of XRD rocking curve measured from symmetry (002) and asymmetry (102) planes are 576 arcsec and 828 arcsec, respectively. To corroborate an enhancement of the growth quality, the FWHM value achieved from the photoluminescence spectra also shows the lowest value (46.5 meV) as compare to other grown samples.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.25 no.3
• /
• pp.302-307
• /
• 1988

A noble interconnection line capacitance measurement method to be able to remove the measurement errors from the probe pad to substrate stray capacitance has been proposed and verified. The measurement errors in the capacitance measurement, which usually be involved from the probe pad to substrate stray capacitance, can easily be removed by isolating the metal probe pad from the substrate with a grounded shield plate between the probe pad the substrate. The measurement results by using this improved capacitance measurement method were compared with the calculations by two-dimensional computer simulations.

• Journal of the Korean institute of surface engineering
• /
• v.28 no.6
• /
• pp.368-375
• /
• 1995

Thermal CVD method is in general used for the fabrication of TiC/$Al_2O_3$-coated carbide tools. The growth of TiC layer and the coating morphology depended on the chemical composition of the hard metal substrate on which the tool properties were strongly influenced. TiC-coated layer was grown by the diffusion of carbon from the substrate, whereas the growth of $Al_2O_3$ layer was unrelated to the composition of substrate. In the nitride hard coatings of Zr, Nb and Mo metals deposited on high speed steel substrate by magnetron sputtering, the reactivity of the metal elements was decreased with increasing group number in one period of the periodic system. The hard material films exhibited the highest adhesion with the chemical composition of stoichiometry or substoichiometry. The critical load as a measure of adhesion was evaluated using scratch tester. The CVD tools indicated the values of 80 and 40N in the coated layers with proper bonding to the substrate and with $\eta$ phase of 1$\mu\textrm{m}$ in the interface respectively, but the nitride films prepared by sputtering of PVD showed only the values between 10 and 20N.

• Applied Science and Convergence Technology
• /
• v.27 no.5
• /
• pp.90-94
• /
• 2018

The electron band structure of manganese-adsorbed graphene on an SiC(0001) substrate has been studied using angle-resolved photoemission spectroscopy. Upon introducing manganese atoms, the conduction band of graphene, that is observed in pristine graphene indicating intrinsic electron-doping by the substrate, completely disappears and the valence band maximum is observed at 0.4 eV below Fermi energy. At the same time, the slope of the valence band decreases by the presence of manganese atoms, approaching the electron band structure calculated using the local density approximation method. The former provides experimental evidence of the formation of nearly free-standing graphene on an SiC substrate, concomitant with a metal-to-insulator transition. The latter suggests that its electronic correlations are efficiently screened, suggesting that the dielectric property of the substrate is modified by manganese atoms and indicating that electronic correlations in grpahene can also be tuned by foreign atoms. These results pave the way for promising device application using graphene that is semiconducting and charge neutral.

• Journal of Magnetics
• /
• v.13 no.4
• /
• pp.140-143
• /
• 2008

The magnetic and structural properties of transition metal (Mn, Fe, Co) monolayers on Ta(001) surfaces are investigated theoretically by using the first principles full-potential linearized augmented plane wave method. Mn and Fe monolayers become ferromagnetic on Ta(001) surfaces while Co monolayers becomes non-magnetic. The paramagnetism of Co monolayers is explained by the Stoner theory of magnetism. The magnetic coupling of a transition metal overlayer with a substrate is ascribed to the orbital hybridization between the s and d orbitals of the transition metal.

• Journal of the Microelectronics and Packaging Society
• /
• v.12 no.3 s.36
• /
• pp.207-212
• /
• 2005

Al, Ti, Ta, and Cr thin films were deposited on a polyimide substrate using DC magnetron sputter to study the adhesion characteristics of metal films on polyimide substrates, while RF bias of 0 - 400 W was applied to the substrate during DC sputtering. The adhesion strength was evaluated using a 90-degree peel test. The peel tests showed that the adhesion strength was enhanced by applying the RF bias to the substrate in all specimens. Scanning electron microscopy and Auger depth profile of the fractured surfaces indicate that the polyimide underwent cohesive failure during peeling and heavy deformation was also observed in the metal films peeled from the polyimide substrate when the RF bias applied during the deposition. Cross-sectional transmission electron microscopy revealed that the metal/polyimide interface was not clear and complicated. This complicated interface, likely formed due to the RF bias applied to the substrate, was attributed to the adhesion enhancement observed during the bias sputtering.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.313-313
• /
• 2016

Transparent conductive oxide (TCO) films have many disadvantages, such as rarity, possible exhaustion, process temperature limitations, and brittleness on a flexible substrate. In particular, as display technology moves toward flexible displays, TCO will become completely unsuitable due to its brittleness. To address theses issue, many researchers have been studying TCO substitutes. In recent efforts, metal nanowires, conducting polymers, carbon nanotube networks, graphene films, hybrid thin films, and metal meshes/grids have been evaluated as candidates to replace TCO electrodes. In this study, we fabricated the TCO film with Ag meshes shape using polystyrene (PS) beads monolayer on the substrate. The PS beads were used as a template to create the mesh pattern. We fabricated the monolayer on the flexible substrate (PES) with the well-aligned PS beads. Electrodes with Ag mesh shape were formed using this patterned monolayer. We could fabricated the Ag mesh electrode with the sheet resistance with $8ohm{\Omega}/{\Box}$.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.439-442
• /
• 2006

We evaluated a-Si:H TFTs fabricated on polyimide substrate (PI) at the highest temperature of $160^{\circ}C$ with uniaxial and tensile strain to imitate flexible display. With tensile strain, the threshold voltage of a-Si:H TFTs have positive shift due to extra dangling bond formation in a-Si:H layer. However, no significant degradation of the subthreshold swing and effective mobility with tensile strain of a-Si:H TFTs indicates the similar level of band tail state. The metal wire with the width of $10\;{\mu}m$ for connection on flexible substrate can sustain with curvature radius 2.5 cm.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 1998.10a
• /
• pp.38-43
• /
• 1998

Magneto Electrolytic Polishing (MEP) is a process in which metal ions are removed from a abrasive through a combination of magnetic electric current and chemical solution. The substrate is immersed into the magnetic effect, chemical solution, and DC crunt is applied. Several factors affect the rate at which the metal ions are removed from the substrate. Three of the most significant are the amount of time in which the substrate is immersed I the solution, and the amount of direct current applied in magnetic field. In this study, the surface finishing characteristics and optical finishing condition for the stainless steel were experimented upon and analyzed.