• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.17 no.8
• /
• pp.875-881
• /
• 2004

Fundamental results obtained from an atomic force microscope (AFM) chemically-induced direct nano-lithography process are presented, which is regarded as a simple method for fabrication nm-scale devices such as superconducting flux flow transistors (SFFTs) and single electron tunneling transistors (SETs). Si cantilevers with Pt coating and with 30 nm thick TiO coating were used as conducting AFM tips in this study. We observed the surfaces of superconducting strip lines modified by AFM anodization' process. First, superconducting strip lines with scan size 2 ${\mu}{\textrm}{m}$${\times}$2 ${\mu}{\textrm}{m}$ have been anodized by AFM technology. The surface roughness was increased with the number of AFM scanning, The roughness variation was higher in case of the AFM tip with a positive voltage than with a negative voltage in respect of the strip surface. Second, we have patterned nm-scale oxide lines on ${YBa}-2{Cu}_3{O}_{7-x}$ superconducting microstrip surfaces by AFM conductive cantilever with a negative bias voltage. The ${YBa}-2{Cu}_3{O}_{7-x}$ oxide lines could be patterned by anodization technique. This research showed that the critical characteristics of superconducting thin films were be controlled by AFM anodization process technique. The AFM technique was expected to be used as a promising anodization technique for fabrication of an SFFT with nano-channel.

• Transactions of Materials Processing
• /
• v.9 no.5
• /
• pp.494-503
• /
• 2000

The electro-magnetic stirring and mechanical process were applied to fabricate particulate metal matrix composites(PMMCs) with various particle size. The mechanical test on PMMCs was carried out in order to clarify the effect of 76 heat treatment on tensile behaviors. In order to study the thixoforming of PMMCs, fabricated billet are reheated by using the coil designed as a function of length between PMMC billet and coil surface, coil diameter and billet length. The effect of reinforcement distribution on billet temperature variation has been investigated with the calculated solid fraction theory based on a function of matrix alloy and volume fraction of reinforcement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2002.07a
• /
• pp.168-171
• /
• 2002

A SSIMT(Suppressed Sidewall Injection Magnetotransistor) sensor with high linearity is presented in this thesis. The prototype is fabricated by using the Hynix 0.6$\mu\textrm{m}$ P-substrate twin-well double poly three-metal CMOS Process. The fabricated SSIMT shows that variation of the collector current is extremely linear by varing the magnetic induction from -200mT to 200mT at I$\_$B/=500${\mu}$A, V$\_$CE/=2V and V$\_$SUB/=5V. The relative sensitivity is up to 120%/T. At B = 0, magnetic offset is about 79mT, there relative sensitivity is 30.5%/T. The nonlinearity of the fabricated SSIMT is measured about 1.4%.

• Proceedings of the IEEK Conference
• /
• 2002.06b
• /
• pp.229-232
• /
• 2002

In this paper, etching characteristics of Zr-silicate in Ar/ClrCH4 plasma is studied, and possible plasma damage is investigated by fabricating MIS capacitors. We'could increase the selectivity to near 2 while keeping the etch rate of Zr-silicate to about 70 nm/min. Leakage current and flat band voltage shift of PUZr-silicate/si capacitors are measured before and after plasma etching. Using capacitor patterns with the same area but different circumference lengths, we try to separate etching damage mechanisms and to optimize the process. The leakage current of 1.2$\times$10-3 A/cm2 and smaller capacitance variation of 0.2 nF at -2V are obtained in Ar/Cl2/CF4 plasma at 200 W RF power

• Proceedings of the IEEK Conference
• /
• 2006.06a
• /
• pp.591-592
• /
• 2006

Schottky diodes for Radio-frequency identification (RFID) tag integration on chip were designed and fabricated using Samsung electronics System LSI standard $0.18{\mu}m$ CMOS process. Schottky diodes were designed as interdigitated fingers array by CMOS layout design rule. 64 types of Schottky diode were designed and fabricated with the variation of finger width, length and numbers with a $0.6{\mu}m$ guard ring enclosing n-well. Titanium was used as Schottky contact metal to lower the Schottky barrier height. Barrier height of the fabricated Schottky diode was 0.57eV. DC current - voltage measurements showed that the fabricated Schottky diode had a good rectifying properties with a breakdown voltage of -9.15 V and a threshold voltage of 0.25 V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.11a
• /
• pp.443-446
• /
• 2003

A 2-Dimensional SSIMT(Suppressed Sidewall Injection Magnetotransistor) sensor with high linearity is presented in this paper. The prototype is fabricated by using the Hynix $0.6{\mu}m$ CMOS Process. The fabricated SSIMT shows that the variation of each collectors current are extremely linear by varing the magnetic induction from -200mT to 200mT at $I_B\;:\;1000{\mu}A,\;V_{CE}\;=\;5V\;and\;V_{SUB}\;=\;5V$. The relative sensitivity is up to 13%/T. At B = 0, magnetic offset is about 40mT, there relative sensitivity is 4.72%/T. The nonlinearity of the fabricated 2-D SSIMT is measured about 1.2%.

• Laser Solutions
• /
• v.10 no.2
• /
• pp.17-24
• /
• 2007

We have studied a laser direct writing lithography(LDWL). This is more important to apply to micro patterning using UV laser. We demonstrate the possibility of LDWL and construct the fabrication system. We use Galvano scanner to process quickly micro patterns from computer data. And laser beam is focused with $F-{\theta}$ lens. AZ5214 and SU-8 photoresist are chosen as experimental materials and a kind of well-known positive and negative photoresist respectively. Laser ablation mechanism depends on the optical properties of polymer. In this paper, therefore we investigate the phenomenon of laser ablation according to the laser fluence variation and measure the shape profile of micro patterned holes. From these experimental results, we show that LDWL is very useful to process various micro patterns directly.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.26 no.9
• /
• pp.1923-1930
• /
• 2002

In this paper, we present modeling and simulation of microlens formation by means of a deep X-ray lithography followed by a thermal treatment of a PMMA (Polymethylmethacrylate) sheet. According to this modeling, X-ray irradiation causes the decrease of molecular weight of PMMA, which in turn decreases the glass transition temperature and consequently causes a net volume increase during the thermal cycle resulting in a swollen microlens. In this modeling, the free volume theory including the relaxation process during the cooling process was considered. The simulation results indicate that the modeling in this study is able to predict the fabricated microlens shapes and the variation pattern of the maximum heights of microlens which depends on the conditions of the thermal treatment. The prediction model could be applied to optimization of microlens fabrication process and to designing a micro mold insert for micromolding processes.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.52 no.2
• /
• pp.56-60
• /
• 2003

In this work, we have fabricated thin film resistors using the DC/RF magnetron sputter of 51wt%Ni-41wt%Cr-8wt%Si alloy target and studied the effect of the process parameters on the electrical properties. In fabrication process, sputtering power, substrate temperature and annealing temperature have been varied as controllable parameters. TCR decreases with increasing the substrate temperature, but TCR increases over 300 [$^{\circ}C$]. The films are annealed to 400 [$^{\circ}C$] in air atmosphere, TCR increases with increasing the annealing temperature. The resistivity was 172 [${\mu}{\Omega}{\cdot}cm$] and 209 [${\mu}{\Omega}{\cdot}cm$] for the RF and DC as a sputtering power sources, respectively. Also, TCR was -52 [$ppm/^{\circ}C$] and -25 [$ppm/^{\circ}C$]. As a results of them, it is suggested that the sheet resistance and TCR of thin films can be controlled by variation of sputter process parameter and annealing of thin film.

• Korean Journal of Optics and Photonics
• /
• v.26 no.4
• /
• pp.209-216
• /
• 2015

A new method is proposed for optimal management of the fabrication and assembly tolerance of optical systems. The practical utility of the method is shown by applying it to a wide-angle anamorphic IR optical system. In this method the wavefront error of an optical system is expressed in terms of Zernike polynomials, and the sensitivity of the expansion coefficients to the variation of design parameters is analyzed. Based on this sensitivity analysis, the optimal tolerances of the fabrication parameters are determined and the best compensators for the assembly process are selected. By using this method, one can accurately predict with good confidence the best possible performance of a completed optical system in practice.