NMOSFET SOI 소자의 Current Kink Effect 감소에 관한 연구

한명석,이충근,홍신남,Han, Myoung-Seok,Lee, Chung-Keun,Hong, Shin-Nam 대한전자공학회 1998 電子工學會論文誌-T Vol.t35 No.2

박막의 SOI(Silicon-On-Insulator) 소자는 짧은 채널 효과(short channel effect), subthreshold slope의 개선, 이동도 향상, latch-up 제거 등 많은 이점을 제공한다. 반면에 이 소자는 current kink effect와 같이 정상적인 소자 동작에 있어 주요한 저해 요소인 floating body effect를 나타낸다. 본 논문에서는 이러한 문제를 해결하기 위해 T-형 게이트 구조를 갖는 SOI NMOSFET를 제안하였다. T-형 게이트 구조는 일부분의 게이트 산화막 두께를 다른 부분보다 30nm 만큼 크게 하여 TSUPREM-4로 시뮬레이션 하였으며, 이것을 2D MEDICI mesh를 구성하여 I-V 특성 시뮬레이션을 시행하였다. 부분적으로 게이트 산화층의 두께가 다르기 때문에 게이트 전계도 부분적으로 차이가 발생되어 충격 이온화 전류의 크기도 줄어든다. 충격 이온화 전류가 감소한다는 것은 current kink effect가 감소하는 것을 의미하며, 이것을 MEDICI 시뮬레이션을 통해 얻어진 충격 이온화 전류 곡선, I-V 특성 곡선과 정공 전류의 분포 형태를 이용하여 제안된 구조에서 current kink effect가 감소됨을 보였다. Thin film SOI(Silicon-on-insulator) device offer unique advantages such as reduction in short channel effects, improvement of subthreshold slope, higher mobility, latch-up free nature, and so on. But these devices exhibit floating-body effet such as current kink which inhibits the proper device operation. In this paper, the SOI NMOSFET with a T-type gate structure is proposed to solve the above problem. To simulate the proposed device with TSUPREM-4, the part of gate oxide was considered to be 30nm thicker than the normal gate oxide. The I-V characteristics were simulated with 2D MEDICI. Since part of gate oxide has different oxide thickness, the gate electric field strength is not same throughout the gate and hence the impact ionization current is reduced. The current kink effect will be reduced as the impact ionization current drop. The reduction of current kink effect for the proposed device structure were shown using MEDICI by the simulation of impact ionization current, I-V characteristics, and hole current distribution.

체외수정 후 출산한 쌍태아의 임상적 고잘

한명석,박은구슬,Han, Myoung-Seok,Park, Eun-Ku-Seul 대한생식의학회 2007 Clinical and Experimental Reproductive Medicine Vol.34 No.3

목 적: 체외수정으로 출산한 쌍태아와 자연임신으로 출산한 쌍태아 간의 산과적 결과의 차이를 비교하고자 한다. 연구방법: 2000년 1월부터 2005년 6월까지 출산한 146건의 쌍태아에 관한 산과적 기록을 검토한 후, 출생 시 재태연령이 24주 이상이며 체외수정으로 임신한 72건을 연구군 (체외수정군), 자연임신한 51건을 대조군 (자연임신이군)으로 나누어 연구를 시행하였다. 결 과: 두 군 간에 산모 연령, 출산 시 재태 연령, 태아체중 등의 차이는 없었지만, 임신성 고혈압과 임신성 당뇨의 발생 위험도는 체외수정군에서 높았다 (OR 2.59; 95% CI 1.01$\sim$6.66). 20% 이상 태아 체중 차이와 같은 성의 쌍태아 발생의 위험도는 체외수정군에서 낮았다 (OR 0.37; 95% CI 0.14$\sim$0.96, OR 0.45; 95% CI 0.21$\sim$0.99). 결 론: 본 연구의 결과로는 체외수정으로 출생한 쌍태아는 자연임신으로 출생한 경우보다 태아 체중 차이의 빈도 및 같은 성 출생의 빈도가 낮았다. Objective: To compare the outcome of twin pregnancies after in-vitro fertilization (IVF) with that of spontaneously conceived twins. Methods: We analyzed 146 twins retrospectively, who had been delivered between January 2000 and July 2005. After reviewing their obstetric medical records, 72 twins conceived with IVF (IVF group) and 51 spontaneously conceived twins (spontaneous group), whose gestational age was over 24 weeks, were recruited for this study. Results: There were no significant statistical differences of demographic features such as maternal age, gestational age and fetal weight between the two groups. However, the risk of pregnancy-induced hypertension (PIH) and gestational diabetes (G-DM) had significantly increased in the group of IVF (OR 2.59; 95% CI 1.01$\sim$6.66). The risk of fetal weight discordancy rate (>20%) and fetal-sex homology rate in IVF group were decreased (OR 0.37; 95% CI 0.14$\sim$0.96, OR 0.45; 95% CI 0.21$\sim$0.99). Conclusion: In this comparative study, maternal PIH and G-DM risks of IVF group are higher than that of spontaneous group. But, fetal-weight discordancy risk and fetal-sex homology rate were lower in IVF group.

고식적 체외수정 시술 시 수정 실패 환자에 대한 세포질내 정자주입술의 효용성

한명석,Han, Myoung-Seok 대한생식의학회 2002 Clinical and Experimental Reproductive Medicine Vol.29 No.2

Objective : This study is to evaluate the efficacy of intracytoplasmic sperm injection (ICSI) for previous fertilization failure with conventional in vitro fetrtilization (IVF), compared with ICSI for male factor. Method: The author analyzed the 3 years of clinical experience with ICSI retrospectively, between the conventional IVF failure group (IVF failure) and male factor group (male factor). Surgically retrieved epididymal or testicular spermatozoa for ICSI were excluded. The IVF failure group was 13 cycles of 6 patients and male factor group was 30 cycles of 15 patients. Results: The fertilization rates of the IVF failure group and male factor group were 63% and 66% respectively (p=0.635). The clinical pregnancy rates of the both group were 23.1% and 26.7% (p=0.804), and that of live birth rates were 15.4% and 13.3% (p=0.858). There were no significant difference between the two groups. Conclusion: The author concluded that ICSI can overcome previous fertilization failure, with the same fertilization and clinical pregnancy rates seen in patients with male factor.

인공수정 시술시 저용량 FSH(Low-dose FSH) 용법의 임상적 효용성에 관한 연구

한명석,Han, Myoung-Seok 대한생식의학회 2001 Clinical and Experimental Reproductive Medicine Vol.28 No.1

Objective: This study is to investigate the clinical efficacy of low-dose FSH regimen, comparing with clomiphene citrate and human menopausal gonadotropin (CC/hMG) regimen. Methods: Retrospective study of the ovulatory factor infertility 39 patients who had been treated by intrauterine insemination (IUI). The 31 cycles of 21 patients were stimulated by CC/hMG regimen, the 22 cycles of 18 patients were stimulated by low-dose FSH regimen. We compared the rate of clinical pregnancy, multiple pregnancy and ovarian hyperstimulation syndrome (OHSS) of both group. Results: The rate of clinical pregnancy of the CC/hMG group was 25.7% per cycle, and that of the low-dose FSH group was 54.5% per cycle. The low-dose FSH group showed a higher rate of clinical pregnancy per cycle than CC/hMG group (p=0.028). However, no differences was found statistically in the rate of multiple pregnancy and OHSS between CC/hMG group (22.2%, 5.7%) and low-dose FSH group (33.3%, 13.6%). Conclusion: This study showed that the low-dose FSH regimen is superior to CC/hMG regimen in getting clinical pregnancy, but dose not reduce the ovulation induction complications.

이중 열처리 방법에 따른 p⁺-n 박막 접합 특성

한명석(Myoung Seok Han),박성종(Sung Jong Park) 대한공업교육학회 2002 대한공업교육학회지 Vol.27 No.2

This dissertation suggests the optimum processing conditions for obtaining good quality shallow p^+-n junctions formed by preamorphization and furnace annealing(FA). Preamorphization was performed by As or Ge ion implantation. And BF_2 ions, the p-type dopant, were implanted with the energy of 20keV, and the dose of 2×10^15cm^-2 into the crystalline and preamorphized silicon substrates. The rapid thermal annealing(RTA) was used to annihilate the crystal defects due to implantation and to activate the implanted boron ions, and the furnace annealing was employed to reflow the boro-phosphosilicate glass(BPSG). The annealing conditions of RTA was 1000℃ for 10sec, and the furnace annealing was used at 850℃ for 40 minutes. Besides the single-step annealing, dual annealings of RTA+FA and FA+RTA were performed. The characteristics of the formed junctions were analyzed with the junction depth, sheet resistance, leakage current, and the products of sheet resistances and junction depth. The single thermal processing with RTA produced shallow junctions of good qualities, and the thermal treatment sequence of FA and RTA yielded better junction characteristics than that of RTA and FA. Ge ion exhibited the better characteristics than As ion. In conclusion, Ge preamorphized samples exhibited the better characteristics than As preamorphized samples. And FA+RTA annealing method have better shallow junction characteristics than RTA+FA method.

열적 효율성에 따른 p⁺-n 접합 다이오드 특성

한명석(Myoung Seok Han),박명호(Myoung Ho Park) 대한공업교육학회 2004 대한공업교육학회지 Vol.29 No.2

자궁경관무력증에 대한 임상적 고찰

한명석 ( Myoung Seok Han ),황태영 ( Tai Young Hwang ) 대한주산의학회 2000 Perinatology Vol.11 No.4

As 선비정질화를 이용한 P<SUP>+</SUP>-N 접합의 특성 고찰

한명석(Myoung Seok HAN),김생환(Saeng Hwan KIM),이창진(Chang Jin LEE),홍신남(Shin Nam HONG) 한국통신학회 1991 한국통신학회 학술대회논문집 Vol.10 No.1

NMOSFET SOI 소자에서 부분적 게이트 산화막 두께 변화에 의한 돌연 전류 효과 고찰

한명석(Myoung-Seok Han),이충근(Chung-Keun Lee),홍신남(Shin-Nam Hong) 대한전자공학회 1998 대한전자공학회 학술대회 Vol.1998 No.11

연령 증가에 따른 dehydroepiandrosterone sulfate와 free testosterone의 농도 변화

한명석 ( Myoung Seok Han ),최일정 ( Il Jung Choi ) 대한산부인과학회 2009 Obstetrics & Gynecology Science Vol.52 No.6

목적: 연령이 증가함에 따른 dehydroepiandrosterone sulfate (DHEAS)와 free testosterone (FT)의 혈중농도 변화에 대해 조사하고자 하였다. 연구 방법: 희발 월경이나 무월경 또는 다모증 등 androgen 과다 증상을 제외한 131명의 여성으로부터 채혈하여 방사선면역측정법을 이용하여 DHEAS와 FT을 측정하였다. P<0.05를 통계적 유의성이 있는 것으로 판단하였다. 결과: 20대 (n=10)의 DHEAS평균은 211.39±33.01 μg/dL, 30대 (n=31)는 127.99±11.79 μg/dL, 40대 (n=57)는 94.30±7.49 μg/dL, 50대 이상 (n=57)은 71.79±5.71 μg/dL이었다 (평균±표준오차, P<0.001). FT농도는 20대에서 3.98±0.94 pg/mL, 30대에서 3.37±0.47 pg/mL, 40대에서 2.68±0.30 pg/mL, 50대 이상은 1.97±0.28 pg/mL이었다 (평균±표준오차, P=0.030). DHEAS의 감소기울기는 r=-0.48865 (P<0.0001)이었으며, FT의 감소기울기는 r=-0.29334 (P<0.0007)이었다. 결론: DHEAS와 FT 혈중 농도는 연령이 증가함에 따라 감소하고 그 감소 정도는 DHEAS가 FT보다 더 크게 나타났다. Objective: To investigate the relationship between serum dehydroepiandrosterone sulfate (DHEAS) or free testosterone (FT) levels and aging. Methods: One hundred and thirty one women without androgen excess symptoms such as oligomenorrhea or amenorrhea or hirsutism were recruited for measuring serum DHEAS, FT levels by radioimmunoassay. A P-value <0.05 was considered to be significant statistically. Results: The levels of DHEAS were 211.39±33.01 μg/dL (twenties, n=10), 127.99±11.79 μg/dL (thirties, n=31), 94.30±7.49 μg/dL (forties, n=57) and 71.79±5.71 μg/dL (over fifties, n=33) respectively (mean±SE, P<0.001). The levels of FT were 3.98±0.94 pg/ml (twenties, n=10), 3.37±0.47 pg/mL (thirties, n=31), 2.68±0.30 pg/mL (forties, n=57) and 1.97±0.28 pg/mL (fifties, n=33) respectively (mean±SE, P=0.030). Mean value declining of DHEAS (r=-0.48865, P<0.0001) was bigger than those of FT (r=-0.29334, P<0.0007). Conclusion: Both DHEAS and FT levels decline with age and DHEAS decreases more steeply than FT.