• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.39-46
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• 2006

Nano-scale fabrication of silicon substrate based on the use of atomic force microscopy (AFM) was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate by a simple scratching process, has been applied instead of conventional silicon cantilever for scanning. A thin mask layer forms in the substrate at the diamond tip-sample junction along scanning path of the tip. The mask layer withstands against wet chemical etching in aqueous KOH solution. Diamond tip acts as a patterning tool like mask film for lithography process. Hence these sequential processes, called tribo-nanolithography, TNL, can fabricate 2D or 3D micro structures in nanometer range. This study demonstrates the novel fabrication processes of the micro cantilever and diamond tip as a tool for TNL using micro-patterning, wet chemical etching and CVD. The developed TNL tools show outstanding machinability against single crystal silicon wafer. Hence, they are expected to have a possibility for industrial applications as a micro-to-nano machining tool.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.339-346
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• 2003

Molecular dynamic simulations of nano indentation on single-crystal silicon (100) surface were performed using diamond indentor. Silicon substrate and diamond indentor were modeled diamond structure with Tersoff potential model. Phase transformation of silicon, incipient plastic deformation, change of incident temperature distribution are investigated through the change of potential energy distribution, displacement-load diagram, the change of kinetic energy distribution and displacements of silicon atoms. Phase transformation is highly localized and consists of a high-density region surrounding the tip. Axial load linearly increased according to the indenting depth. Number of atoms with high kinetic energy increased at the interface between substrate and indentor tip.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.95-96
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• 2009

A fully depleted capacitorless 1-transistor dynamic random access memory (FD 1T-DRAM) based on a sSOI strained-silicon-on-insulator) wafer was investigated. The fabricated device showed excellent electrical characteristics of transistor such as low leakage current, low subthreshold swing, large on/off current ratio, and high electron mobility. The FD sSOI 1T-DRAM can be operated as memory device by the floating body effect when the substrate bias of -15 V is applied, and the FD sSOI 1T-DRAM showed large sensing margin and several milli seconds data retention time.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.4
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• pp.169-172
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• 2003

Silicon nanocrystalline thin films on p-type (100) silicon substrate have been fabricated by pulsed laser deposition technique using a Nd:YAG laser with the wavelength of 355, 532, and 1064 nm. The base vacuum in the chamber was down to $10^-6$ Torr and the laser energy densities were 1.0~3.0 J/$\textrm{cm}^2$ After deposition, silicon nanocrystalline thin films have been annealed at nitrogen gas. Strong Blue and green luminescence from silicon nanocrystalline thin films have been observed at room temperature by photoluminescence and its peak energies shift to green when the wavelength is increased from 355 to 1064 nm.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.4
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• pp.361-364
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• 2008

Tips of probe card were fabricated using MEMS technology. P-type silicon wafer with $SiO_2$ layer was used as a substrate for fabricating the probe card. Ni-Cr and Au used as seed layer for electroplating Ni were deposited on the silicon wafer. Line patterns for probing devices were formed on silicon wafer by electroplating Ni through mold which formed by MEMS technology. Bridge structure was formed by wet-etching the silicon substrate. AZ-1512 photoresist was used for protection layer of back side and DNB-H100PL-40 photoresist was used for patterning of the front side. The mold with the thickness of $60{\mu}m$ was also formed using THB-120N photoresist and probe tip with thickness of $50{\mu}m$ was fabricated by electroplating process.

• Proceedings of the IEEK Conference
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• 2003.07b
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• pp.1065-1068
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• 2003

For the first time, high quality ultra-thin strained Si/SiGe on Insulator (SGOI) substrate with total SGOI thickness( $T_{Si}$ + $T_{SiGe}$) of 13 nm is developed to combine the device benefits of strained silicon and SOI. In the case of 6- 10 nm-thick top silicon, 100-110 % $I_{d,sat}$ and electron mobility increase are shown in long channel nFET devices. However, 20-30% reduction of $I_{d,sat}$ and electron mobility are observed with 3 nm top silicon for the same long channel device. These results clearly show that the FETs operates with higher performance due to the strain enhancement from the insertion of SiGe layer between the top silicon layer and the buried oxide(BOX) layer. The performance degradation of the extremely thin( 3 nm ) top Si device can be attributed to the scattering of the majority carriers at the interfaces.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.2
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• pp.131-133
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• 1994

Deposition of silicon on pretreated sapphire substrates has been investigated by the liquid phase epitaxy method at low temperatures. An average 14 $\mu\textrm{m}$ thickness of silicon was grown over a large area on sapphire substrate originally coated with a much thinner silicon layer $[0.5 \mu\textrm{m} (100) Si/(1102) sapphire]$ at low temperatures from $(380^{\circ}C to 460^{\circ}C)$.

• Journal of electromagnetic engineering and science
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• v.2 no.2
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• pp.59-64
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• 2002

In this paper, 10$\mu$ m-elevated MEMS CPWs on various substrates are presented. Effective dielectric constants of elevated CPW(ECPW) on polyimide-loaded silicon or alumina substrate are examined and characteristic impedances are also computed versus elevation height. Dispersive property of ECPW and its electromagnetic field distributions are studied through 3-D FDTD algorithm for optimum design. Attenuation of ECPW is measured with TRL calibration procedure and revealed about 3.2 43 lower than that of conventional CPW on the same low-resistivity silicon at 40 CHz. ECPW on polyimide-loaded silicon with overlapped configuration reveals 0.2 dB/mm. Especially, alumina substrate imposes better attenuation than silicon.

• ETRI Journal
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• v.33 no.5
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• pp.802-805
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• 2011

This letter presents a K-band polarization reconfigurable antenna integrated with a silicon radio frequency MEMS switch into the form of a compact package. The proposed antenna can change its state from linear polarization (LP) to circular polarization (CP) by actuating the MEMS switch, which controls the configuration of the coupling ring slot. Low-loss quartz is used for a radiating patch substrate and at the same time for a packaging lid by stacking it onto the MEMS substrate, which can increase the system integrity. The fabricated antenna shows broadband impedance matching and exhibits high axial ratios better than 15 dB in the LP and small axial ratios in the CP, with a minimum value of 0.002 dB at 20.8 GHz in the K-band.

• Korean Journal of Materials Research
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• v.34 no.3
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• pp.144-151
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• 2024

This work focuses on the fabrication of excellent magnetic structures for trapping breast cancer cells. Micromagnetic structures were patterned for trapping cancer cells by depositing 30 nm of permalloy on a silicon substrate. These structures were designed and fabricated using two fabrication techniques: electron beam lithography and laser direct writing. Two types of magnetic structures, rectangular wire and zig-zagged wire, were created on a silicon substrate. The length of each rectangular wire and each straight line of zig-zagged wire was 150 ㎛ with a range of widths from 1 to 15 ㎛ for rectangular and 1, 5, 10 and 15 ㎛ for zigzag, respectively. The magnetic structures showed good responses to the applied magnetic field despite adding layers of silicon nitride and polyethylene glycol. The results showed that Si + Si₃N₄ + PEG exhibited the best adhesion of cells to the surface, followed by Si + Py + Si₃N₄ + PEG. concentration of 5-6 with permalloy indicates that this layer affected silicon nitride in the presence of Polyethylene glycolPEG.