• Title/Summary/Keyword: Bias-stress

Search Result 291, Processing Time 0.033 seconds

Deposition of DLC film by using an FCVA system with a magnetic mirror and characterization of its material properties (거울형 자계 구조를 갖는 진공 여과 아크 증착법을 이용한 다이아몬드상 탄소 박막의 증착 및 물성 분석)

  • PARK, Chang-Kyun;UHM, Hyun-Seok;SEO, Soo-Hyung;PARK, Jin-Seok
    • Proceedings of the KIEE Conference
    • /
    • 2000.07c
    • /
    • pp.1717-1719
    • /
    • 2000
  • DLC films are deposited by using an FCVA deposition system with a mirror-type magnetic field configuration. Permanent magnets and: magnetic yokes around the cathode have been observed to enhance the mobility of arc spots on the cathode and the stability of arc plasma, Effects of reactor pressures and substrate biases on structural properties of DLC films deposited are investigated. The results show that the highest $sp^{3}/sp^{2}$ fraction is obtained when the films are deposited at a pressure of $3{\times}10^4$ Torr and a bias voltage of - 50 V. The variation of the structural properties due to thermal stress up to 500$^{\circ}C$ is also examined.

  • PDF

A Characteristics on Impedance of Degraded Thyristor with Heat and Voltage Stress (열화된 사이리스터 소자의 임피던스 특성)

  • Seo, Kil-Soo;Kim, Hyung-Woo;Kim, Ki-Hyun;Kim, Nam-Kyun
    • Proceedings of the KIEE Conference
    • /
    • 2006.07c
    • /
    • pp.1351-1352
    • /
    • 2006
  • In this paper, the impedance properties of degraded thyristor with heat and voltage were presented. As degraded thyristor, 8 thyristors with each other different reverse blocking voltage used. Its impedance and resistance properties were measured from frequency 100Hz to 10MHz applied with bias voltage from 0V to 40V. As a result, at low frequency region, that is, at the frequency 100-10kHz, the abrupt increasement of its capacitance was confirmed. And also, at high frequency region, the capacitance peak move toward low frequency in the region of frequency 4 - 6MHz as degradation of thyristor.

  • PDF

Electrical Characteristics of Ultra-thin $SiO_2$ Films experienced Hydrogen or Deuterium High-pressure Annealing (고압의 수소 및 중수소 분위기에서 열처리된 실리콘 산화막의 전기적 특성 관찰)

  • Lee, Jae-Sung;Baek, Jong-Mu;Do, Seung-Woo;Jang, Cheol-Yeong;Lee, Yong-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2005.07a
    • /
    • pp.29-30
    • /
    • 2005
  • Experimental results are presented for the degradation of 3 nm-thick gate oxide ($SiO_2$) under both Negative-bias Temperature Instability(NBTI) and Hot-carrier-induced(HCI) stresses using P and NMOSFETs that are annealed with hydrogen or deuterium gas at high-pressure (1~5 atm.). Statistical parameter variations depend on the stress conditions. We suggest that deuterium bonds in $SiO_2$ film is effective in suppressing the generation of traps related to the energetic hot electrons.

  • PDF

Controlling Electrical Properties in Zinc Oxide Thin Films by Organic Concentration

  • Yun, Gwan-Hyeok;Han, Gyu-Seok;Jeong, Jin-Won;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2013.08a
    • /
    • pp.209.2-209.2
    • /
    • 2013
  • We proposed and fabricated zinc oxide thin-film transistors (TFTs) employing 4-mercaptophenol (4MP) doped ZnO by atomic layer deposition (ALD) that results in highly stable and high performance. The 4MP concentration in ZnO films were varied from 1.7% to 5.6% by controlling Zn:4MP pulses. The n-type carrier concentrations in ZnO thin films were controlled from $1.017{\times}10^{20}/cm^3$ to $2.903{\times}10^{17}/cm^3$ with appropriate amount of 4MP doping. The 4.8% 4MP doped ZnO TFT revealed good device mobility performance of 8.4 $cm^2/Vs$ and the on/off current ratio of 106. Such 4MP doped ZnO TFTs exhibited relatively good stability (${\Delta}V_{th}$: 2.4 V) under positive bias-temperature stress while the TFTs with only ZnO showed a 4.3 ${\Delta}V_{th}$ shift, respectively.

  • PDF

Effect of Prenatal Dexamethasone on Sex-specific Changes in Embryonic and Placental Growth

  • Yun, Hyo Jung;Lee, Ji-Yeon;Kim, Jongsoo;Kim, Myoung Hee
    • Biomedical Science Letters
    • /
    • v.20 no.1
    • /
    • pp.43-47
    • /
    • 2014
  • To understand the effect of prenatal stress on sex-specific changes in embryonic and placental growth, a synthetic glucocorticoid (dexamethasone) was administered intraperitoneally at a dosage of 1 mg/kg body weight (BW) (Dex1) or 10 mg/kg BW (Dex10) to pregnant ICR mice at the gestational days 7.5, 8.5 and 9.5 post coitum (p.c.). Embryos and placentas were then harvested at days 11.5 and 18.5 p.c., and their body weight and size were measured following the determination of sex through PCR using Sry specific primers in tail tissues. As a result, female embryos presented reduced fetal body weight and size in Dex1- and Dex10-treated groups than those of control group at the embryonic day 11.5 p.c. Interestingly, the growth seems to be recovered at day 18.5 as there was no difference in growth between control and dexamethasone treated groups. In the case of males, Dex1 induced a decrease in fetal weight in day 11.5 and this pattern was maintained until day 18.5, whereas their growth was not affected by Dex10 treatment. Placental growth showed similar patterns to fetal growth in both sexes but the extent of reduction was not statistically significant in most cases. Placental weights in Dex1- and Dex10-treated group were decreased significantly in male only. The results imply that the effect of prenatal stress is largely sex dependent due to different strategies for growth and survival in a stressful environment.

Simulations Analysis of Proposed Structure Characteristics in Shallow Trench Isolation for VLSI (고집적을 위한 얕은 트랜치 격리에서 제안한 구조의 특성 모의 분석)

  • Lee, YongJae
    • Journal of the Korea Society for Simulation
    • /
    • v.23 no.3
    • /
    • pp.27-32
    • /
    • 2014
  • In this paper, We are going to propose the novel structure with improved behavior than the conventional vertical structure for VLSI CMOS circuits. For this, the proposed structure is the moat shape for STI. We want to analysis the characteristics of simulations about the electron concentration distribution, oxide layer shape of hot electron stress, potential flux and electric field flux, electric field fo themal damage and current-voltage characteristics in devices. Physically based models are the ambient and stress bias conditions of TCAD tool. As a analysis results, shallow trench structure were trended to be electric functions of passive as device dimensions shrink. The electrical characteristics influence of proposed STI structures on the transistor applications become stronger the potential difference electric field and saturation threshold voltage, are decreased the stress effects of active region. The fabricated device of based on analysis results data were the almost same characteristics of simulation results data.

Effects of thermal treatment on structural and electrical properties of DLC films deposited by FCVA method (FCVA 방법으로 증착된 DLC 박막의 열처리에 따른 구조적, 전기적 물성 분석)

  • Kim, Young-Do;Chang, Seok-Mo;Park, Chang-Kyun;Uhm, Hyun-Seok;Park, Jin-Seok
    • Proceedings of the KIEE Conference
    • /
    • 2002.07c
    • /
    • pp.1536-1538
    • /
    • 2002
  • Effects at thermal treatment on the structural and electrical properties at DLC films have been studied. The DLC films were deposited by using a modified FCVA system as a function at negative substrate bias voltage, deposition time, and nitrogen flow rate. The thermal treatment on DLC films could be achieved by performing the RTA process at $600^{\circ}C$, 2min. Structural investigation on the thermal treatment effect was evaluated by inspecting the Raman spectroscopy, XPS, AFM, and internal compressive stress. In addition, the electrical properties of DLC films were evaluated by using the high current source and Lab-View data acquisition system. As the result at RTA treatment, $sp^3/sp^2$ ratio and internal compressive stress of the DLC films were decreased tram 5% to 22% and from 1GPa to 3GPa, and the $I_D/I_G$ intensity ratios was increased from 0.19 to 0.35. It was also found that the variation of internal stress of DLC films strongly agree with the variation of $sp^3/sp^2$ fraction and $I_D/I_G$ intensity ratio.

  • PDF

Role of Oxytocin in Post-traumatic Stress Disorder: A Systematic Review (외상 후 스트레스 장애에 대한 옥시토신의 역할: 체계적 문헌 고찰)

  • Oh, Jaeuk;Kim, Minsu;Chu, Sang Hui
    • Journal of Korean Biological Nursing Science
    • /
    • v.24 no.1
    • /
    • pp.1-16
    • /
    • 2022
  • Purpose: Recently, oxytocin has been introduced experimentally as a pharmacological treatment for post-traumatic stress disorder (PTSD). This study attempted to investigate the possibility of oxytocin as a treatment option for patients with PTSD by examining its dose, interval, and effectiveness in patients with PTSD. Methods: A systematic review was done on articles published from 1967 to 2020 using the PubMed, PsycINFO, and Cochrane databases. Our inclusion criteria were 1) subjects 18 years of age or older diagnosed with PTSD or exposed to a traumatic event that met criterion A of the Diagnostic and Statistical Manual of Mental Disorders (DSM) for PTSD, 2) oxytocin was administered at least once, 3) clinical trials, and 4) studies published in Korean or English. Two independent researchers reviewed 22 articles and recorded the contents. The risk of bias was evaluated to determine the quality of the reviewed article. Results: The parameters for evaluating the effectiveness of oxytocin were identified as socio-behavioral measures in 11 articles, neuronal imaging in 9, and biomarkers in 4. In 5 papers, oxytocin was administered multiple times. Socio-behavioral measures were improved in 3 out of 5 studies in which oxytocin was administered multiple times. In 2 studies in which prolonged exposure treatment and nasal oxytocin administration were combined for 10 weeks, patient symptoms were decreased compared to the control group. Conclusion: The possibility of oxytocin as an adjuvant treatment for PTSD psychotherapy was confirmed. Further studies are necessary to evaluate the long term effectiveness of administering oxytocin multiple times combined with psychotherapy.

Improvement of Electrical Performance and Stability in ZnO Channel TFTs with Al Doped ZnO Layer (Al Doped ZnO층 적용을 통한 ZnO 박막 트랜지스터의 전기적 특성과 안정성 개선)

  • Eom, Ki-Yun;Jeong, Kwang-Seok;Yun, Ho-Jin;Kim, Yu-Mi;Yang, Seung-Dong;Kim, Jin-Seop;Lee, Ga-Won
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.28 no.5
    • /
    • pp.291-294
    • /
    • 2015
  • Recently, ZnO based oxide TFTs used in the flexible and transparent display devices are widely studied. To apply to OLED display switching devices, electrical performance and stability are important issues. In this study, to improve these electrical properties, we fabricated TFTs having Al doped Zinc Oxide (AZO) layer inserted between the gate insulator and ZnO layer. The AZO and ZnO layers are deposited by Atomic layer deposition (ALD) method. I-V transfer characteristics and stability of the suggested devices are investigated under the positive gate bias condition while the channel defects are also analyzed by the photoluminescence spectrum. The TFTs with AZO layer show lower threshold voltage ($V_{th}$) and superior sub-threshold slop. In the case of $V_{th}$ shift after positive gate bias stress, the stability is also better than that of ZnO channel TFTs. This improvement is thought to be caused by the reduced defect density in AZO/ZnO stack devices, which can be confirmed by the photoluminescence spectrum analysis results where the defect related deep level emission of AZO is lower than that of ZnO layer.

Improvement of Electronic Properties and Amplification of Electron Trapping/Recovery through Liquid Crystal(LC) Passivation on Amorphous InGaZnO Thin Film Transistors

  • Lee, Seung-Hyeon;Kim, Myeong-Eon;Heo, Yeong-U;Kim, Jeong-Ju;Lee, Jun-Hyeong
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2016.02a
    • /
    • pp.267.1-267.1
    • /
    • 2016
  • 본 연구에서는 nematic 액정의 종류 중 하나인 5CB (4-Cyano-4'-pentylbiphenyl) 물질을 박막 트랜지스터 (TFT)의 passivation 층으로 사용했을 때 그 전기적 특성향상을 확인하였다. RF-magnetron sputtering법으로 증착된 비정질 InGaZnO 박막을 활성층으로 사용한 TFT를 제작하여 그 활성층 위에 drop형식으로 passivation 하였다. 그 결과, drain current (I_DS)가 약 10배 정도 증가하고, linear region(V_D=0.5V)에서 mobility와 subthreshold slope(SS)이 각각 6.7에서 12.2, 0.3에서 0.2로 향상되는 것이 보였다. 이것은 gate bias가 인가되었을 때 freedericksz 전이를 통한 액정의 배향과 이때 형성된 dipole 형성에 의한 것으로 보이며, 이러한 LC의 배향은 편광현미경을 통하여 표면과 수직으로 배향한다는 사실을 확인 할 수 있었고 이 LC-passivation된 a-IGZO TFT의 전기적 특성의 향상에 대한 mechanism을 제시하였다. 그리고 배향한 LC가 가지는 dipole에 의해 bias stress 상황에서 독특한 electron trapping과 recovery의 증폭효과가 나타났다. V_G=+20V의 positive gate bias stress를 1000s동안 가했을 때, passivation되지 않은 a-IGZO TFT의 경우 +4V의 threshold voltage shift(${\Delta}V$_TH)가 발생되었고, 바로 -20V의 negative gate bias를 30s간 가해주었을 때 -2.5V의 ${\Delta}V$_TH가 발생하였다. 반면 LC-passivation된 a-IGZO TFT의 경우 각각 +5V와 -4V의 ${\Delta}V$_TH로 더 큰 변화를 가져왔다. 이러한 LC에 의한 electron trapping/recovery 증폭효과에 대한 model을 제시하였다.

  • PDF