• Title/Summary/Keyword: DRE

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Effect of surface damage remove etching of Reactive Ion Etching for Crystalline silicon solar cell

  • Park, Jun-Seok;Byeon, Seong-Gyun;Park, Jeong-Eun;Lee, Yeong-Min;Lee, Min-Ji;Im, Dong-Geon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.404-404
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    • 2016
  • 태양전지 제작 시 표면에 피라미드 구조를 형성하면 입사되는 광의 흡수를 높여 광 생성 전류의 향상에 기여한다. 일반적인 KOH를 이용한 습식 표면조직화 공정은 평균 10%의 반사율을 보였으며, 유도 결합 플라즈마를 이용한 RIE 공정은 평균 5.4%의 더 낮은 반사율을 보였다. 그러나 RIE 공정을 이용한 표면조직화는 낮은 반사율과 서브 마이크론 크기의 표면 구조를 만들 수 있지만 플라즈마 조사에 의한 표면 손상이 많이 발생하게 된다. 이러한 표면 손상은 태양전지 제작 시 표면에서 높은 재결합 영역으로 작용하게 되어 포화 전류(saturation currents, $J_0$)를 증가시키고 캐리어 수명(carrier lifetime, ${\tau}$)을 낮추는 결함 요소로 작용한다. 이러한 플라즈마에 의한 표면 손상을 제거하기 위해 HF, HNO3, DI-water를 이용하여 DRE(Damage Remove Etching) 공정을 진행하였다. DRE 공정은 HF : DI-water 솔루션과 HNO3 : HF : DI-water 솔루션의 두 가지 공정을 이용하여 공정 시간을 가변하며 진행하였다. 포화전류($J_0$), 캐리어 수명(${\tau}$), 벌크 캐리어 수명(Bulk ${\tau}$)을 비교를 하기위해 KOH, RIE, RIE + DRE 공정을 진행한 세 가지 샘플로 실험을 진행하였다. DRE 공정을 적용할 경우 공정 시간이 지날수록 반사도가 높아지는 경향을 보였지만, 두 번째의 최적화된 솔루션 공정에서 $2.36E-13A/cm^2$, $42{\mu}s$$J_0$, Bulk ${\tau}$값과 가장 높은 $26.4{\mu}s$${\tau}$를 얻을 수 있었다. 이러한 결과는 오제 재결합(auger recombination)이 가장 많이 발생하는 지역인 표면과 불균일한 도핑 영역에서 DRE 공정을 통해 나아진 표면 특성과 균일한 도핑 프로파일을 형성하게 되어 재결합 영역과 $J_0$가 감소 된 것으로 판단된다. 높아진 반사도의 경우 $SiN_x$를 이용한 반사방지막을 통해 표면 반사율을 1% 이내로 내릴 수 있어 보완이 가능하였다. 본 연구에서는 RIE 공정 중 플라즈마에 의해 발생하는 표면 손상 제거를 통하여 캐리어 라이프 타임의 향상된 조건을 찾기 위한 연구를 진행하였으며, 기존 RIE 공정에 비해 반사도의 상승은 있지만 플라즈마로 인한 표면 손상을 제거하여 오제 재결합에 의한 발생하는 $J_0$를 낮출 수 있었고 높은 ${\tau}$값인 $26.4{\mu}s$의 결과를 얻어 추후 태양전지 제작에 향상된 효율을 기대할 수 있을 것으로 기대된다.

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Protective Effect of Dioscoreae Rhizoma Extracts in MIA-induced Rat. (MIA로 유발된 골관절염 동물모델에서 산약 추출물의 골관절염 개선 효과)

  • Kim, Min Ju;Park, Hae-Jin;Kim, Kyeong Jo;Lee, Jin A;Shin, Mi-Rae;Roh, Seong-Soo
    • The Korea Journal of Herbology
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    • v.34 no.4
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    • pp.27-35
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    • 2019
  • Objectives : Osteoarthritis is characterized by degeneration of articular cartilage, which is characterized by chronic pain, stiffness and decrease range of motion. The present study was designed to compare the therapeutic effect of Dioscoreae Rhizoma water extract (DRW) and Dioscoreae Rhizoma 30% ethanol extract (DRE) on the monosodium iodoacetate (MIA)-induced osteoarthritis rats. Methods : Osteoarthritis was induced by injection of MIA ($50{\mu}{\ell}$ with $80mg/m{\ell}$) into the knee joint cavity of rats. After adaptation period for seven days, rats were divided by 5 groups (n=10/group): normal group, control group, positive control (indomethacin 5 mg/kg), DRW 200 mg/kg treated group, DRE 200 mg/kg treated group (n=10/group). The hind paw weight distribution was measured with the changes of reactive oxygen species (ROS), peroxynitrite ($ONOO^-$) in articulation tissue. Also, the cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), tumor necrosis factoralpha ($TNF{\alpha}$), interleukin-6 (IL-6), matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of metalloproteinases-1 (TIMP-1) were investigated by western blot analysis. Results : The administration of DRW and DRE significantly decreased the hind paw weight distribution. The ROS and $ONOO^-$ levels of cartilaginous tissue were significantly decreased in DRW and DRE compared to control group. The results showed that DRE decreased inflammatory cytokines such as iNOS and $TNF{\alpha}$. Also DRE decreased MMP-1 and increased TIMP-1. Conclusions : Based on the above results, Dioscoreae Rhizoma extract seems to have the therapeutic effect on osteoarthritis via suppression of inflammation.

Characteristics of Antidiabetic Effect of Dioscorea rhizoma(1) - Hypoglycemic Effect - (산약의 항당뇨 특성 연구(1) - 혈당 강하 효과 -)

  • Kang, Tong-Ho;Choi, Sang-Zin;Lee, Tae-Ho;Son, Mi-Won;Kim, Sun-Yeou
    • The Korean Journal of Food And Nutrition
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    • v.21 no.4
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    • pp.425-429
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    • 2008
  • Diabetes mellitus is a group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Type 1 diabetes, or juvenile-onset diabetes, results from a cellular-mediated autoimmune destruction of the ${\beta}$-cells of the pancreas. Type 2 diabetes, or adult-onset diabetes, is a term used for individuals who have insulin resistance, a condition that makes it harder for the cells to properly use insulin, and usually have relative insulin deficiency. The diabetes causes the onset of chronic complications and diabetic neuropathy is one of the most debilitating complications. In this study, the hypoglycemic effect and the preventive effect of diabetic complications of Dioscorea rhizoma extract(DRE) were examined in rodent model. We investigated the glucose tolerance test and long term hypoglycemic effect of DRE in Type 1 streptozotocin-induced diabetic rats and Type 2 diabetic db/db mice. DRE showed a hypoglycemic effect on blood glucose levels than that of control group in Type 1 streptozotocin-induced diabetic rats and Type 2 diabetic db/db mice. On the basis of our results, we conclude that long-term use of DRE might help decrease blood glucose level and prevention of diabetes-associated complication.

Global Warming Gas Emission during Plasma Cleaning Process of Silicon Nitride Using C-C$_4$F$_8$O Feed Gas with Additive $N_2$

  • Kim, K.J.;C.H. Oh;Lee, N.E.;Kim, J.H.;J.W. Bae;G.Y. Yeom;S.S. Yoon
    • Journal of the Korean institute of surface engineering
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    • v.34 no.5
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    • pp.403-408
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    • 2001
  • In this work, the cyclic perfluorinated ether (c-C$_4$F$_{8}$O) with very high destructive removal efficiency (DRE) than other alternative gases, such as $C_3$F$_{8}$, c-C$_4$F$_{8}$ and NF$_3$ was used as an alternative process chemical. The plasma cleaning of silicon nitride using gas mixtures of c-C$_4$F$_{8}$O/O$_2$ and c-C$_4$F$_{8}$O/O$_2$+ $N_2$ was investigated in order to evaluate the effects of adding $N_2$ to c-C$_4$F$_{8}$O/O$_2$ on the global warming effects. Under optimum condition, the emitted net perfluorocompounds (PFCs) during cleaning of silicon nitride were quantified and then the effects of additive $N_2$ by obtaining the destructive removal efficiency (DRE) and the million metric tons of carbon equivalent (MMT-CE) were calculated. DRE and MMTCE were obtained by evaluating the volumetric emission using. Fourier transform-infrared spectroscopy (FT-IR). During the cleaning using c-C$_4$F$_{8}$O/O$_2$+$N_2$, DRE values as high as (equation omitted) 98% were obtained and MMTCE values were reduced by as high as 70% compared to the case of $C_2$F$_{6}$O$_2$. Recombination characteristics were indirectly investigated by combining the measurements of species in the chamber using optical emission spectroscopy (OES), before and after the cleaning, in order to understand any correlation between plasma and emission characteristics as well as cleaning rate of silicon nitride.silicon nitride.

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Abatement of CF4 Using RF Plasma with Annular Shape Electrodes Operating at Low Pressure (환상형상 전극구조를 갖는 저압 RF plasma를 이용한 CF4 제거)

  • Lee, Jae-Ok;Hur, Min;Kim, Kwan-Tae;Lee, Dae-Hoon;Song, Young-Hoon;Lee, Sang-Yun;Noh, Myung-Keun
    • Journal of Korean Society for Atmospheric Environment
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    • v.26 no.6
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    • pp.690-696
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    • 2010
  • Abatement of perfluorocompounds (PFCs) used in semiconductor and display industries has received an attention due to the increasingly stricter regulation on their emission. In order to meet this circumstance, we have developed a radio frequency (RF) driven plasma reactor with multiple annular shaped electrodes, characterized by an easy installment between a processing chamber and a vacuum pump. Abatement experiment has been performed with respect to $CF_4$, a representative PFCs widely used in the plasma etching process, by varying the power, $CF_4$ and $O_2$ flow rates, $CF_4$ concentration, and pressure. The influence of these variables on the $CF_4$ abatement was analyzed and discussed in terms of the destruction & removal efficiency (DRE), measured with a Fourier transform infrared (FTIR) spectrometer. The results revealed that DRE was enhanced with the increase in the discharge power and pressure, but dropped with the $CF_4$ flow rate and concentration. The addition of small quantity of $O_2$ lead to the improvement of DRE, which, however, leveled off and then decreased with $O_2$ flow rate.

Transcriptional Regulation of the Drosophila Proliferating Cell Nuclear Antigen Gene and raf Proto-oncogene by Ursolic Acid in Drosophila Cultured Kc Cells

  • Park, Thae-Yeong;Rhee, Sang-Hoon;Kim, Han-Do;Kim, Chong-Rak;Kang, Ho-Sung;Yoo, Mi-Ae
    • Animal cells and systems
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    • v.1 no.1
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    • pp.151-155
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    • 1997
  • Promoter of the Drosophila proliferating cell nuclear antigen (PCNA) gene contains DRE (Drosophila DNA replication-related element) required for the high level expression of replication-related genes. Recently, we found that promoter region of the D-raf (a Drosophila homolog of the human c-raf-1) contains two sequences homologous to the DRE and demonstrated the DRE/DREF (DRE-binding factor) involvement in regulation of the D-raf gene. In this study, using ursolic acid (UA), a pentacyclic triterpene acid reported to possess antitumor activities, we examined effects of UA on proliferation of the Drosophila cultured Kc cells and on expression of the PCNA and D-raf genes. UA showed an inhibitory effect on proliferation of the Kc cells in a concentration-dependent manner in DNA content assays and [3H]thymidine incorporation assays. The IC50 value of anti-proliferative effects of UA in DNA content assays was about 7.5uM. UA showed inhibitory effects on expression of the PCNA as well as on that of the D-raf, which were examined with the reporter plasmic p5'-168DPCNACAT or p5'-878DrafCAT, respectively. The results obtained in the present study suggest that expression of the PCNA and D-raf genes is coordinately regulated in at least UA-treated Kc cells and that down-regulation of expression of the PCNA and D-raf genes might be related with the antitumor activities of UA.

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Destruction of $NF_3$ Emitted from Semiconductor Process by Electron Beam Technology (전자빔 기술을 이용한 반도체 공정의 삼불화질소($NF_3$) 분해)

  • Ryu, Jae-Yong;Choi, Chang-Yong;Kim, Jong-Bum;Lee, Sang-Jun;Kim, Seung-Gon;Kwak, Hee-Sung;Yun, Young-Min
    • Journal of Korean Society of Environmental Engineers
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    • v.34 no.6
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    • pp.391-396
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    • 2012
  • The destruction study of $NF_3$ gas emitted from the semiconductor industry is performed with electron-beam technology. Absorbed dose (kGy) and current ranged from 0 (0) to 400 kGy (20 mA). The concentration of $NF_3$ gas ranged from 500 to 2,000 ppm. In order to assess the effect of a residence time on DRE (Destruction and Removal Efficiency, %), experiments also conducted at different irridiation times of 5 sec, 10 sec, 15 sec and 20 sec respectively. As absorbed dose and current increased, DRE of $NF_3$ was also increased. However, DRE (%) of $NF_3$ decreased with increasing the concentration of $NF_3$ gas. The DRE of $NF_3$ was about 90% at an absorbed dose of 400 kGy.

Micro blaster를 이용한 태양전지용 재생웨이퍼의 표면 개선에 관한 연구

  • Lee, Yun-Ho;Jeong, Dong-Geon;Jo, Jun-Hwan;Gong, Dae-Yeong;Seo, Chang-Taek;Jo, Chan-Seop;Lee, Jong-Hyeon
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.293-293
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    • 2010
  • 최근 태양전지 연구에서 저가격화를 실현하는 방법 중 하나로 폐 실리콘 웨이퍼를 재생하는 방법에 관하여 많은 연구가 진행되고 있다. 그러나 기존 웨이퍼 재생공정은 높은 재처리 비용과 복잡한 공정등의 많은 단점을 가지고 있다. 챔버 내에 압축된 공기나 가스에 의해 가속된 미세 파우더들이 재료와 충돌하면서 식각하는 기계적 건식 식각 공정 기술이라고 할 수 있는 micro blaster 공정을 이용하면 기존 재생공정보다 낮은 재처리 비용과 간단한 공정으로 재생웨이퍼를 제작할 수 있다. 하지만 이러한 micro blaster 공정은 식각 후 표면에 많은 particle과 crack을 형성시켜 태양전지용으로 사용하기에 단점을 가진다. 본 연구에서는 이러한 micro blaster를 이용한 태양전지용 재생 웨이퍼를 제작하기 위해 폐 실리콘 웨이퍼의 표면 물질을 식각하고, 식각 후 충돌에 의해 발생된 표면의 particle과 crack을 DRE(Damage Remove Etching)공정으로 제거하는 연구를 진행 하였다. 먼저 폐 실리콘 웨이퍼와 같은 표면을 형성하기 위하여 시편 표면에 각각 Al($2000{\AA}$), $Si_3N_4(3000{\AA})$, $SiO_2(1{\mu}m)$, AZ1512($1{\mu}m$)을 형성하고 micro blaster의 파우더 크기, 압력, 스캔 속도 등의 공정 조건에 따라 폐 실리콘 웨이퍼 표면 물질을 식각하였다. 식각 후 폐 실리콘 웨이퍼의 식각된 깊이와 표면 물질 잔량을 측정하고, 폐 실리콘 웨이퍼의 표면에 particle과 crack, 요철이 형성되어 있는지를 확인하였다. 그 결과 폐 실리콘 웨이퍼에 형성된 물질의 두께 이상으로 식각되었으며, 표면 물질의 잔량이 남아 있지 않았고, 표면에 많은 particle과 crack, 요철이 형성되었다. 표면에 형성된 요철은 유지하면서 많은 particle과 crack을 제거하기 위하여 micro blaster공정 후 DRE 공정으로 표면 개선이 필요하였다. 이때 남겨진 요철은 입사광량을 증가시키고, 표면 반사율을 감소시켜 태양전지내의 흡수하는 빛의 양을 증가시키는 태양전지 texturing 공정 효과로 작용하게 된다. 표면에 남은 particle과 crack을 완전히 제거하면서 요철은 유지할 수 있게 HNA 용액의 농도와 시간에 따른 식각 정도를 측정하였다. DRE 공정 후 표면 particle과 crack이 완전히 제거되어 표면이 개선됨을 확인하였다. Micro blaster를 이용하여 폐 실리콘 웨이퍼의 표면을 식각하고, DRE공정으로 표면을 개선함으로써 태양전지용 기판으로의 재생 가능성을 확인하였다.

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A Study on Increase of Sulfur Hexafluoride(SF6) Destruction and Removal Efficiency by Conditioning Agent(H2) (수소첨가에 의한 육불화황(SF6) 분해효율 향상 기초연구)

  • Ryu, Jae-Yong;Kim, Jong-Bum;Choi, Chang-Yong;Jang, Seong-Ho;Lee, Sang-Joon
    • Journal of Environmental Science International
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    • v.21 no.9
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    • pp.1163-1169
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    • 2012
  • Destruction and removal efficiency (DRE) of $SF_6$ was tested with low degrees of ionization. The applied dose of ionization energy varied from 63.70 to 212.34 kGy. The initial concentration and flow rate of $SF_6$ gas were 1,000 ppm and 50L/min, respectively. In order to increase the DRE, injection of conditioning agent ($H_2$) were conducted. The DRE of $SF_6$ increased about 2 times with injection of $H_2$ gas.

Effectiveness of the Transrectal Ultrasonography in the Detection of Prostate Cancer: in Patients with Prostate Specific Antigen of 10 ng/ml or Less (전립선암 발견에 있어 경직장 초음파 검사의 유용성: 전립선특이항원 수치가 10 ng/ml 이하인 환자를 대상으로)

  • Chang, Han-Won;Cho, Jae-Ho
    • Journal of Yeungnam Medical Science
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    • v.21 no.2
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    • pp.191-197
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    • 2004
  • Background: This study was performed to reconsider the efficacy of transrectal ultrasonography (TRUS) in diagnosing prostate cancer by analyzing the results of a digital rectal examination (DRE), serum prostate-specific antigen (PSA) and a transrectal ultrasonography in patients with prostate specific antigen levels of 10 ng/ml or less. Materials and Methods: One-hundred and eighty one men with PSA levels of 10 ng/ml or less, who had a TRUS-guided tissue biopsy performed, were included in this study. The detection rate of prostate cancer was compared according to the TRUS result and the presence or absence of nodularity and the consistency of the prostate on DRE. Results: In a total 181 patients, there were 73 patients with PSA levels of 4 ng/ml or less and 4 of them had prostate cancer. Thre were 108 patients with PSA levels of 4-10 ng/ml and 18 of them were prostate cancer. TRUS was performed in 152 patients and 16 out of 58 patients diagnosed with prostate cancer, 3 out of 39 diagnosed with suspicious prostate cancer, and 2 out of 55 patients diagnosed as having no prostate cancer were found to have prostate cancer. In 40 patients, a nodule was palpated on DRE and 8 of them were found to have prostate cancer. Five out of 19 patients with a stony hard consistency, 3 of 12 with a firm to hard consisency, 12 of 129 with a firm consistency, 0 of 13 with a soft to firm consistency, and 2 of 8 with a soft consistency were prostate cancer. In the prostate cancer patients, there were 4 patients with PSA levels of 4 ng/ml or less and all these patients were diagnosed with prostate cancer or suspicious prostate cancer on TRUS but the nodule was not palpated in all patients. Two were soft and 2 were firm consistency on DRE. Conclusion: In patients with serum PSA levels of 10 ng/ml or less, TRUS is a more useful supporting method than DRE and a more active application of TRUS may lead to an early diagnosis and pertinent treatment of prostate cancer.

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