• Proceedings of the Materials Research Society of Korea Conference
• /
• 2008.05a
• /
• pp.34.1-34.1
• /
• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.11a
• /
• pp.155-156
• /
• 2007

• ETRI Journal
• /
• v.13 no.4
• /
• pp.35-41
• /
• 1991

저전력 고집적 GaAs 디지틀 IC에 적합한 기본 논리회로인 DCFL (Direct Coupled FET Logic) 을 구현하기 위한 소자로 WSi게이트 MESFET 공정을 연구하였으며, 이와 함께 TiPtAu 게이트 소자를 제작하였다. MESFET 의 제작은 내열성게이트를 이용한 자기정렬 이온주입 공정을 사용하였으며 주입된 Si 이온은 급속열처리 방법으로 활성화하였다. 또한 제작공정중 저항성 접촉의 형성은 절연막을 이용한 리프트 - 오프 공정을 이용하였다. 제작된 WSi게이트 MESFET은 $1\mum$ 게이트인 경우 222mS/mm의 트랜스컨덕턴스를 나타내어 우수한 동작특성과 집적회로 공정의 적합성을 보였으며 이와 동등한 공정조건으로 제작된 TiPtAu 게이트 MESFET 은 2" 기판 내에서 84mV의 임계전압 변화를 나타내었다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.196.1-196.1
• /
• 2015

전 세계적으로 환경에 대한 인식이 증대됨에 따라 친환경적인 소재의 개발 연구가 필요한 상황이고, 대표적으로 셀룰로오스를 이용한 종이기판을 활용하는 방안이 새로운 연구화두로 떠오르고 있다. 종이를 기본으로 한 전기전자 회로구성의 가능성을 보기위해 종이 위해 전자회로 구성요소를 형성시켜야 할 필요가 있다. 이를 위해 본 연구팀은 상용 복사 용지위에 마이크로 단위의 패터닝을 구현하는 연구를 진행하였다. 마이크로 패터닝 구현 방법은 다음과 3가지로 요약할 수 있다;1. 리소그래피 공정, 2. 메탈마크스를 사용한 물질 증착, 3. 잉크젯 프린팅. 리소그래피 공정을 위해서 발수처리를 한 종이 위에 실리콘기반 공정과 마찬가지로 레지스트를 코팅하고 노광과 디벨롭, 증착과 리프트오프 과정을 거쳤다. 공정 결과 패터닝이 어느 정도 잘 되는 것을 확인할 수 있었다. 두번째로 상용 메탈마스크를 제작하여 종이 위에 그대로 증착하는 방법을 사용하였다. 이 방법은 액상공정을 요구하지 않기 때문에 발수처리가 필요하지 않고 종이의 기본성질을 그대로 유지 할 수 있다는 장점이 있다. 마지막으로 잉크젯 프린팅 공정은 복사용지를 인쇄할 때 사용하는 간단한 상용프린터를 이용하였다. 이 방법은 앞의 두 공정보다는 다소 패턴 사이즈가 크다는 단점이 있지만 원하는 모양을 자유롭게 패터닝 할 수 있고 그만큼 대량 생산에 용이하다는 장점이 있다.

• Korean Journal of Optics and Photonics
• /
• v.24 no.5
• /
• pp.224-230
• /
• 2013

Laser Lift-Off (LLO) is a process that removes a GaN or AIN thin layer from a sapphire wafer to manufacture vertical-type LEDs. It consists of a light source, an attenuator, a mask, a projection lens and a beam homogenizer. In this paper, we design an attenuator and a projection lens. We use the 'ZEMAX' optical design software for analysis of depth of focus and for a projection lens design which makes $7{\times}7mm^2$ beam size by projecting a beam on a wafer. Using the 'LightTools' lighting design software, we analyze the size and uniformity of the beam projected by the projection lens on the wafer. The performance analysis found that the size of the square-shaped beam is $6.97{\times}6.96mm^2$, with 91.8 % uniformity and ${\pm}30{\mu}m$ focus depth. In addition, this study performs dielectric coating using the 'Essential Macleod' to increase the transmittance of an attenuator. As a result, for 23 layers of thin films, the transmittance total has 10-96% at angle of incidence $45-60^{\circ}$ in S-polarization.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.18 no.9
• /
• pp.2197-2202
• /
• 2014

In this paper, we report on an investigation of highly sensitive sensing performance of a hydrogen sensor composed of palladium (Pd) nanowires. The Pd nanowires have been grown by electrodeposition into nanochannels and liberated from the anodic aluminum oxide (AAO) template by dissolving in an aqueous solution of NaOH. A combination of photo-lithography, electron beam lithography and a lift-off process has been utilized to fabricate the sensor using the Pd nanowire. The hydrogen concentrations for 2% and 0.1% were obtained from the sensitivities (${\Delta}R/R$) for 1.92% and 0.18%, respectively. The resistance of the Pd nanowires depends on absorption and desorption of hydrogen. Therefore, we expect that the Pd nanowires can be applicable for detecting highly sensitive hydrogen gas at room temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.506-508
• /
• 2005

In general, organic TFTs are comprised of four components: gate electrode, gate dielectric, organic active semiconductor layer, and source and drain contacts. The TFT current, in turn, is typically determined by channel length and width, carrier field effect mobility, gate dielectric thickness and permittivity, contact resistance, and biasing conditions. More recently, a number of techniques and processes have been introduced to the fabrication of OTFT circuits and displays that aim specifically at reduced fabrication cost. These include microcontact printing for the patterning of metals and dielectrics, the use of photochemically patterned insulating and conducting films, and inkjet printing for the selective deposition of contacts and interconnect pattern. In the fabrication of organic TFTs, microcontact printing has been used to pattern gate electrodes, gate dielectrics, and source and drain contacts with sufficient yield to allow the fabrication of transistors. We were fabricated a pentacene OTFTs on flexible PEN film. Au/Cr was used for the gate electrode, parylene-c was deposited as the gate dielectric, and Au/Cr was chosen for the source and drain contacts; were all deposited by ion-beam sputtering and patterned by microcontact printing and lift-off process. Prior to the deposition of the organic active layer, the gate dielectric surface was treated with octadecyltrichlorosilane(OTS) from the vapor phase. To complete the device, pentacene was deposited by thermal evaporation and patterned using a parylene-c layer. The device was shown that the carrier field effect mobility, the threshold voltage, the subthreshold slope, and the on/off current ratio were improved.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.28 no.2
• /
• pp.184-190
• /
• 2008

Various ECT techniques have been applied basically to assess the integrity of steam generator tithing in nuclear power plant. Among these techniques, the bobbin probe technique is applied generally to examine the volumetric flaws such as a crack-like defect and wear which is generally occurred on steam generator tubing, and additionally MRPC probe is used to examine closely tile top of tubesheet and bending regions due to the high possibility of cracking. Dent and bulge also may be formed on tube during installation process and operation of steam generator, but the dent and bulge indications greater than specific size criteria are recorded on examination report because these indications are not considered as flaw. These indications can be easily detected with bobbin probe and approximately sized with profile bobbin probe, but the size and shape can not be accurately verified. Accordingly, in this study, the $8{\times}1$ multi-array EC probe was designed to increase the measurement accuracy of the sectional profiling EC testing of tube. As a result, we would like to propose the application of $8{\times}1$ multi-array EC probe for the measurement of size and shape of profile change on steam generator tube in OPR-1000 nuclear power plant.