• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.311-311
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• 2009

Carbon nanotubes (CNTs) belong to an ideal material for field emitters because of their superior electrical, mechanical, and chemical properties together with unique geometric features. Several applications of CNTs to field emitters have been demonstrated in electron emission devices such as field emission display (FED), backlight unit (BLU), X-ray source, etc. In this study, we fabricated a CNT cathode by using filtration processes. First, an aqueous CNT solution was prepared by ultrasonically dispersing purified single-walled CNTs (SWCNTs) in deionized water with sodium dodecyl sulfate (SDS). The aqueous CNT solution in a milliliter or even several tens of micro-litters was filtered by an alumina membrane through the vacuum filtration, and an ultra-thin CNT film was formed onto the alumina membrane. Thereafter, the alumina membrane was solvated by acetone, and the floating CNT film was easily transferred to indium-tin-oxide (ITO) glass substrate in an area defined as 1 cm with a film mask. The CNT film was subjected to an activation process with an adhesive roller, erecting the CNTs up to serve as electron emitters. In order to measure their luminance characteristics, an ITO-coated glass substrate having phosphor was employed as an anode plate. Our field emitter array (FEA) was fairly transparent unlike conventional FEAs, which enabled light to emit not only through the anode frontside but also through the cathode backside, where luminace on the cathode backside was higher than that on the anode frontside. Futhermore, we added a reflecting metal layer to cathode or anode side to enhance the luminance of light passing through the other side. In one case, the metal layer was formed onto the bottom face of the cathode substrate and reflected the light back so that light passed only through the anode substrate. In the other case, the reflecting layer coated on the anode substrate made all light go only through the cathode substrate. Among the two cases, the latter showed higher luminance than the former. This study will discuss the morphologies and field emission characteristics of CNT emitters according to the experimental parameters in fabricating the lamps emitting light on the both sides or only on the either side.

• 방사선산업학회지
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• 제6권1호
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• pp.31-40
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• 2012

There are two methods to fabricate the readout electronic to a large-area CMOS image sensor (LACIS). One is to design and manufacture the sensor part and signal processing electronics in a single chip and the other is to integrate both parts with bump bonding or wire bonding after manufacturing both parts separately. The latter method has an advantage of the high yield because the optimized and specialized fabrication process can be chosen in designing and manufacturing each part. In this paper, LACIS chip, that is optimized design for the latter method of fabrication, is presented. The LACIS chip consists of a 3-TR pixel photodiode array, row driver (or called as a gate driver) circuit, and bonding pads to the external readout ICs. Among 4 types of the photodiode structure available in a standard CMOS process, $N_{photo}/P_{epi}$ type photodiode showed the highest quantum efficiency in the simulation study, though it requires one additional mask to control the doping concentration of $N_{photo}$ layer. The optimized channel widths and lengths of 3 pixel transistors are also determined by simulation. The select transistor is not significantly affected by channel length and width. But source follower transistor is strongly influenced by length and width. In row driver, to reduce signal time delay by high capacitance at output node, three stage inverter drivers are used. And channel width of the inverter driver increases gradually in each step. The sensor has very long metal wire that is about 170 mm. The repeater consisted of inverters is applied proper amount of pixel rows. It can help to reduce the long metal-line delay.

• Korean Chemical Engineering Research
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• 제43권4호
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• pp.531-536
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• 2005

포토리지스트 마스크로 패턴된 CoTb 및 CoZrNb 자성 박막에 대한 유도 결합 플라즈마 반응성 이온 식각이 $Cl_2/Ar$와 $C_2F_6/Ar$ 가스를 이용하여 진행되었고 식각 속도와 식각 프로파일 측면에서 조사되었다. $Cl_2$와 $C_2F_6$ 가스의 농도가 증가함에 따라서 자성 박막들의 식각 속도는 감소하였고 식각 경사는 낮아졌다. 자성 박막들의 식각 가스로서 $Cl_2/Ar$이 빠른 식각 속도와 가파른 식각 경사를 얻는데 있어서 $C_2F_6/Ar$ 보다 더 효과적이었다. Coil rf power의 증가는 플라즈마 내의 Ar 이온과 라디칼의 밀도를 증가시키고 dc bias voltage의 증가는 기판으로 스퍼터되는 Ar 이온의 에너지를 증가시키기 때문에 coil rf power와 dc bias voltage가 증가할수록 식각 속도와 식각 경사는 증가하였지만 패턴의 측면에서 재증착이 일어났다. 자성 박막들의 적층으로 형성된 magnetic tunnel junction stack에 고밀도 플라즈마 반응성 이온 식각을 적용하여, 높은 식각 경사와 재증착이 없는 깨끗한 식각 프로파일을 얻었다.