• 한국세라믹학회지
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• 제29권4호
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• pp.273-282
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• 1992

The effects of intrinsic and extrinsic gettering on the formation of microdefects in the wafer and on the electrical performance at near-surfaces of three different oxygen-bearing Czochralski silicon single crystal wafers were investigated by varying the combinations of the pre-heat treatments and the phosphorus diffusion through the back-surface of the wafers. The wafers which had less than 10.9 ppma of oxygen formed no gettering zones irrespective of any pre-heat treatments, while the wafers which had more than 14.1 ppma of oxygen and were treated by Low+High pre-heat treatments generated the gettering zone comprising oxygen precipitates, staking faults, and dislocation loops. The effects of extrinsic gettering by phosphorus diffusion were evident in all samples such that the minority carrier lifetimes were increased and junction leakage currents were decreased. However, the total gettering effects among the different pre-heat treatments did not necessarily correspond to the gettering structure revealed by synchrotron radiation section topograph.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 하계학술대회 논문집
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• pp.162-165
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• 1991

Oxygen behaviors in CZ-silicon wafer, grown by the Lucky Advanced Materials Inc. that is a pioneer of silicon material industries in Korea, were investigated to simulate effects on the device performance of oxygen, neglecting the effect of other impurity content, defects and thermal history. Silicon wafers were annealed through simulated 16K SRAM thermal cycle. As initial oxygen concentration increased up to 16.7ppma the amount of oxygen precipitation increased up to 10.6ppma and the bulk microdefect density increased up to $10.3{\times}10^3/mm^2$, but the depth of the denuded zone decreased to $5.0{\mu}m$

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 학술대회지
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• pp.675-679
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• 2004

The existing conjugated blue emitting material polymer which has been used for the two-wavelength method white-emission has good stability and low operating voltage as merits, but the imbalanced carrier transport has been indicated as problem area. We have introduced a novel blue emitting material having perylene moiety unit with hole transporting ability and blue emitting property and triazine moiety unit with electron transporting ability into the same host chain. We have synthesized N-[p-(perylen-3-y1)pheny1]methacry1 amide (PPMA) monomer and [N-(2,4-dipheny1-1,3,5-triazine)pheny1 methacry1 amide] (DTPM) monomer having blue light-emitting unit and electron transport unit, respectively by three steps. A novel non-conjugated blue emitting material Poly[N -[p­(perylene-3-y1) pheny1] methacry1 amide-co-N-[P-(4,6-dipheny1-1,3,5-triazine-2-y1]pheny1]methacry1 amide] (PPPMA-co-DTPM) copolymer having electron transporting unit was synthesized by the solution polymerization of PPMA and DTPM monomers with an AIBN initiator and showed high yield of $75{\%}$. It was very soluble in common organic solvents, and the fabrication of the thin film using a spin coating method was very simple. The PPPMA exhibited a good thermal stability.

• 한국결정성장학회지
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• 제24권6호
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• pp.246-251
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• 2014

최근 태양전지의 효율을 증가시키기 위한 연구가 많이 이루어지고 있으며, 특히 단결정 실리콘 웨이퍼의 경우 높은 효율을 낼 수 있는 소재로써 고효율 태양전지연구에 많이 이용되고 있다. 본 연구에서는 단결정으로 Czochralski(Cz)-Si 성장 시 산소농도를 다르게 하여 산소석출결함의 변화와 그에 따른 셀효율과의 관계를 비교하였다. 산소불순물은 Cz법으로 성장시킨 실리콘의 주된 불순물이다. 산소불순물 존재 시 태양전지 공정에서 산소석출결함이 생성되며 발생된 산소석출결함은 셀효율에 악영향을 미치게 된다. 그러므로 고효율 태양전지를 위한 웨이퍼를 생산하기 위한 산소석출결함 밀도와 셀효율의 상관성을 연구하였다. 또한 산소농도에 따른 산소석출결함을 분석하여 산소석출결함이 발생되지 않는 잉곳 내 산소농도 범위를 연구하여 14.5 ppma 이하에서 Bulk Micro Defect(BMD)가 발생하지 않음을 확인하였다.

• 한국재료학회지
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• 제2권2호
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• pp.119-125
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• 1992

수평자장을 건 Czochralski(HMCZ) 방법으로 자장강도(B)와 도가니 회전속도(C)가 실리콘 단결정의 산소편석에 미치는 영향에 대하여 연구하였다. B=2, 3, 4kG와 C=4-15rpm에서 <100> 방향으로 성장시킨 57mm 직경의 단결정들 내의 산소분포는 대체로 축을 따라서 불균일하였고 톱니모양을 나타내었다. 종래의 CZ 방법과 비교할 때, 이러한 산소분포의 불균일성은 위 강도의 수평자장이 결정성장계면으로의 산소전달에 불안정한 요소로 작용했음을 나타낸다고 볼 수 있다. 반면에 C의 증가는 산소분포의 불균일성의 약화와 산소농도의 전반적인 증가를 유도하였다. 이 결과를 토대로 B=2kG에서 27-36ppma인 산소분포를 가진 단결정이 프로그램된 C에 의해서 얻어졌다. 소자제조공정을 모의한 열처리 과정에서 HMCZ 실리콘의 산소석출은 종래의 CZ 실리콘의 산소석출에 비해서 상대적으로 불균일하였고, as-grown 상태에서의 고르지 못한 HMCZ 실리콘의 산소분포가 주요 원인임이 밝혀졌다.

• 유변학
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• 제10권2호
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• pp.57-64
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• 1998

A pultrusion resin impregnation (PRI) die, which has been developed recently in our laboratory, was used to pre-pare various composite system. The continuous fiber reinforced composites of glass fiber/polypropylene(GFPP) and glass fiber/polyamide 6 (GFPA) were first manufactured by means of the PRI die and then cut into chopped pellets of predet-ermined length. These pellets and either virgin or modified thermoplastic resin were melt-mixed by a twin screw extruder to prepare GF/PA/PP and GF/PA/PPMA system. The mechanical properties of these blends were investigated and discussed in terms of their morphological observations. These preliminary results revealed that this new impregnation die could be suc-cessfully applied to produce prepregs suitavle for the final shaping process.

• 한국전기전자재료학회논문지
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• 제18권7호
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• pp.641-646
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• 2005

To fabricate a single layer white organic light emitting diode (OLED), a novel non-conjugated blue emitting material PPPMA-co-DTPM copolymer was synthesized containing a perylene moiety unit with hole transporting and blue emitting ability and a triazine moiety unit with electron transporting ability. The devices were fabricated using PPPMA-co-DTPM $(PPPMA[70\;wt\%]:DTPM[30\;wt\%])$ copolymer by varying the doping concentrations of each red, green and blue fluorescent dye, by molecular-dispersing into Toluene solvent with spin coating method. In case of ITO/PPPMA-co-DTPM:TPB$(3\;mol\%):C6(0.04\;mol\%):NR(0.015\;mol\%)/Al$ structure, as they were molecular-dispersing into 30 mg/ml Toluene solvent, nearly-pure white light was obtained both (0.325, 0.339) in the CIE coordinates at 18 V and (0.335, 0.345) at 15 V. The turn-on voltage was 3 V, the light-emitting turn-on voltage was 4 V, and the maximum external quantum efficiency was $0.667\%$ at 24.5 V. Also, in case of using 40 mg/ml Toluene solvent, the CIE coordinate was (0.345, 0.342) at 20 V.

• 한국결정성장학회지
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• 제18권5호
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• pp.195-199
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• 2008

반도체용 규소 원료는 11 N급의 고순도이나 가격이 고가이고 또한 생산이 제한되어서 폭발적인 태양전지의 수요를 따르지 못하고 있어 저급(5$\sim$6 N)의 UMG(Upgraded Metallurgical Grade)를 사용하자 하는 노력이 진행 중이다. 이 5$\sim$6 N급에서는 dopant 원소인 붕소(B)외 인(P)의 농도가 1 ppm 이상 존재한다. 이들 원료를 사용하여서 결정 성장을 하였을 경우에 존재하는 여러 불순물들의 편석계수(segregation coefficient)를 활용하여 화학적, 전기적 성질을 예상 하여본 결과 결정성장 초기에는 붕소(B)의 농도가 인(P) 보다 높아 p영역이 발생하고 후반부에는 인의 농도가 붕소 보다 높아 n 형 기판이 생성됨을 보았다. 또한 응고속도를 조절하여 여러 불순물을 제거하고자 히는 노력은 편식계수가 적은 금속 일소들의 제거에는 효과적이나 편석계수가 큰 붕소와 인의 제거에는 효과가 크지 않음을 예상 할 수 있다.

• 전자공학회논문지D
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• 제36D권4호
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• pp.48-56
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• 1999

본 논문에서는 초기 산소 농도가 고에너지 이온 주입시 결정 격자 손상에 의해 발생하는 산소 축적(pileup) 현상 및 주입된 불순물의 확산에 미치는 영향을 실험적으로 고찰하였다. 초기 산소 농도가 11.5, 15.5 ppma인 p-type (100)실리콘 웨이퍼에 \sup 11\B\sup +\ \sup 31\P\sup +\ 이온을 각각 1.2 MeV, 2.2 MeV 의 에너지로 1×10\sup 15\cm\sup 2\ 주입하고, 700℃(20시간)+1000℃(10시간)의 2단계 열처리를 거치 후 주입된 불순물 및 산소 농도의 분포를 이차이온질량분석기 (Secondary Ion Mass Spectrometry, SIMS)로 관찰하였으며 잔류 2차 결함의 분포는 투과전자현미경(Transmission Electron Microscopy, TEM)으로 관찰하였다. SIMS 측정 결과 산소의 축적이 {{{{ { R}_{ } }}}}\sub p\(projected range) 부근에서 관찰되었으며 열처리 후에도 상당한 양의 2차 결합 띠가 {{{{ { R}_{ } }}}}\sub p\부근에서 관찰되는 것으로 보아 2차 결함에 의해 산소가 포획되었음을 알 수 있다. 또한 붕소와 인의 확산은 웨이퍼의 초기 산소 농도가 클수록 벌크 방향으로의 확산이 증대되는 현상을 볼 수 있었다.

• Applied Science and Convergence Technology
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• 제26권5호
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• pp.110-113
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• 2017

The two-dimensional layered $MoS_2$ has high mobility and excellent optical properties, and there has been much research on the methods for using this for next generation electronics. $MoS_2$ is similar to graphene in that there is comparatively weak bonding through Van der Waals covalent bonding in the substrate-$MoS_2$ and $MoS_2-MoS_2$ heteromaterial as well in the layer-by-layer structure. So, on the monatomic level, $MoS_2$ can easily be exfoliated physically or chemically. During the $MoS_2$ field-effect transistor fabrication process of photolithography, when using water, the water infiltrates into the substrate-$MoS_2$ gap, and leads to the problem of a rapid decline in the material's yield. To solve this problem, an epoxy-based, as opposed to a water-based photoresist, was used in the photolithography process. In this research, a hydrophobic $MoS_2$ field effect transistor (FET) was fabricated on a hydrophilic $SiO_2$ substrate via chemical vapor deposition CVD. To solve the problem of $MoS_2$ exfoliation that occurs in water-based photolithography, a PPMA sacrificial layer and SU-8 2002 were used, and a $MoS_2$ film FET was successfully created. To minimize Ohmic contact resistance, rapid thermal annealing was used, and then electronic properties were measured.