• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1993.05a
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• pp.113-116
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• 1993

A guided - wave electro - optical modulatored directional coupler $2{\times}2$ was fabricated on X-cut $LiNbO_3$ by proton exchange wi th self-aligned method. The Electode pattern was formed by the four extra gap electrode separtion within self-aligned electrode mask. Initial cross over state turned that by controlling the anneal ing process and self-aligned electrodes are used in fabricating the electro-optical modulatored directional coupler $2{\times}2$. The modulatored directional coupler $2{\times}2$ has very good figures of merits: the measured crosstalk was -28.2 dB and the modulating valtage of 3.2[V].

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.62-63
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• 2008

Photonic crystas were fabricated using an anodic aluminum oxide(AAO) mask on GaN diode. The Photonic crystal structure has been investigated from Atomic Force Microscope(AFM). The hole diameter and lattice constant of photonic crystal are 60nm and 105nm, respectively. Photoluminescence of photonic crystal was enhanced and optical interference was increased by photonic crystal effect.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.123-123
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• 2008

In this work, amorphous carbon thin films were deposited for hard mask applications by a reactive particle beam (RPB) assisted sputtering system at room temperature. The depositing characteristics of the films were investigated as functions of operating parameters such as reflector bias voltage and RF plasma power. It was confirmed that the deposition rate increased with increasing the reflector bias voltage and RF plasma power. By an atomic force microscope (AFM), it was revealed that the surface roughness was also increased. The total stress in films was determined by the use of the substrate curvature and its result will be discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.195-198
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• 2003

본 연구에서는 MILC 및 FALC를 도핑 타입에 따른 온도별 패턴별 인가 전압별로 진행하여 현미경 및 FESEM 관찰을 함으로써 그 메커니즘을 규명하고자 하였다. LPCVD를 이용하여 $1000\;{\AA}$ a-Si 을 glass에 입힌 후 photolithography법 또는 Hard Mask법으로 Ni $200\;{\AA}$ 을 선택적으로 증착하였으며 Pt 전극을 Sputtering법으로 제작하였다. $33\;{\sim}\;200\;V/cm$의 전기장 하에서 MILC 속도가 2배 정도 증가되는 현상이 관찰되었으며 또한 인접패턴에 의해 FALC 속도가 영향을 받는 현상이 관찰되었다. 또한 전자가 움직이는 방향으로 MILC 선단영역 전후에 Void가 발생하는 영역이 존재함을 발견하였다. FESEM 분석을 통하여 FALC 영역 및 Void 영역을 관찰한 결과 도핑 종류에 따라 결정화 양상이 다른 것이 관찰되었으며 Void 분석결과 Charged vacancy가 어닐링시 결집되어 나타나는 것으로 분석할 수 있었다.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.10
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• pp.881-886
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• 2003

This paper describes the design and implementation of a passive transponder chip for RFID applications. Passive transponders do not have their own power supply, and therefore all power required for the operation of a passive transponder must be drawn from the field of the reader. The designed transponder consists of a full wave rectifier to generate a dc supply voltage, a 128-bit mask ROM to store the information, and Manchester coding and load modulation circuits to be used for transmitting the information from the transponder to the reader. The transponder with a size 410 x 900 ${\mu}$m$^2$ has been fabricated using 0.65 ${\mu}$m 2-poly, 2-metal CMOS process. The measurement results show the data transmission rate of 3.9 kbps at RF frequency 125 kHz.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.10
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• pp.853-858
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• 2003

In this study, a new simplified technology for fabricating high density trench gate DMOSFETs using only three mask layers and TEOS/nitride spacer is proposed. Due to the reduced masking steps and self-aligned process, this technique can afford to fabricate DMOSFETs with high cell density up to 100 Mcell/inch$^2$ and cost-effective production. The resulting unit cell pitch was 2.3∼2.4${\mu}$m. The fabricated device exhibited a excellent specific on-resistance characteristic of 0.36m$\Omega$. cm$^2$ with a breakdown voltage of 42V. Moreover, time to breakdown of gate oxide was remarkably increased by the hydrogen annealing after trench etching.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.93-96
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• 1996

We developed three dimensional Monte carlo ion implantation simulator which simulate distributions of impurities under the ion implantation on the tilted multi-layered layer. Our simulation reveals three dimensional shadow effect and sidewall scattering effect due to the geometrical shapes. For the evaluation of the developed three dimensional Monte carlo ion implantation simulator, calculations with 100,000 ions have been performed for the island and hole structures with a thin oxide of 100$\AA$ and nitride of 2000$\AA$. The simulation results showed that the distribution of ion decreases near the conner of the hole structure covered with a nitride layer and increases near the conner for the island structure open to oxide. Moreover, three dimensional distributions of ions were obtained with varying incident energy, tilt and rotation angle, mask depth and three-dimensional structure geometry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.40-43
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• 1996

Substrates of SAW filter are mainly single crystal such as LiNbO$_3$, LiTaO$_3$. However, fabrication of crystal is difficult and cost is very high. In this study, crystal was substituted for piezoelectric ceramics which has simple fabrication process. The same SAW filter mask was photolithographed on crystal(LiNbO$_3$) substrate and ceramic(PZT4, PZT5A and PZT8) substrate in order to compare experimental value with theoretical value. The difference of center frequency was only 3.7%. PZT8 showed good bandwidth properties. It is considered that PZT8 has higher mechanical quality factor and propagation velocity than PZT4, PTT5A.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.497-500
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• 1999

This paper reports on the fabrication and characteristics of recessed gate GaN MESFETs fabricated using a photoelectrochemical wet etching method. The unique etching process utilizes photo-resistive mask and KOH based etchant. GaN MESFETs with successfully recessed gate structure was characterized in terms of dc and RF performance. The fabricated GaN MESFET exhibits a current saturation at $V_{DS}$ = 4 V and a pinch-off at $V_{GS}$ =-3V The peak drain current of the device is about 230mA/mm at 300 K and the value is remained almost same for 500K operation. The $f_{T}$ and $f_{max}$ from the device are 6.357Hz and 10.25 GHz, respectively.y.y.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.91-95
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• 1998

Selectivity of SiC deposition on a Si substrate partially covered with a masking material was investigated by introducing HCl gas into hexamethyldisilane/H2 gas system during the deposition. the schedule of the precursor and HCl gas flows was modified so that the selectivity of SiC deposition between a Si substrate and a mask material should be improved. It was confirmed that the selectivity of SiC deposition was improved by introducing HCl gas. Also, the pulse gas flow technique was effective to enhance the selectivity.