• 한국재료학회지
• /
• 제5권6호
• /
• pp.633-638
• /
• 1995

열산화 및 PECVD법으로 p-type(100)Si wafer위에 $Ta_2O_{5}$, 박막을 형성한 후 이들 박막의 전기적 특성과 박막응력 상호간의 관계를 연구하였다 열산화 시편의 경우 dc magnetron sputtering법으로 Ta을 증착시킨 후에 산화온도와 시간을 변수로 열산화시켜 박막을 형성시켰으며 PECVD 시편의 경우 RF power density를 변화시켜가면서 박막을 형성시켰다. 이들 박막의 전기적 특성과 박막응력을 조사하여 전기적 특성과 박막응력 상호간의 관계를 조사한 결과 열산화 박막의 경우 누설전류와 박막응력은 독립적인데 반해 PECVD 박막의 경우 박막응력의 절대값은 누설전류가 증가함에 따라 증가하였다.

• 한국재료학회지
• /
• 제9권6호
• /
• pp.551-555
• /
• 1999

The deposition condition to obtain stoichiometric $Ta_2$O\ulcorner films, which is still controversial, using magnetron reactive sputtering was studied. The films were deposited by varying $O_2$gas flow rate with sputtering power and Ar gas flow rate of 200W and 60 sccm fixed. At the conditions of $O_2$ gas flow rate over 20 sccm, amorphous Tantalum oxide films with the refractive index of 2.1 and dielectric constant of 25 were deposited. Among those films, the capacitors dielectric properties of the film deposited at the condition of $O_2$ gas flow rate 50 sccm was best, the leakage current was 1$\times$10\ulcornerA/$\textrm{cm}^2$ at the electric field strength of 0.5 MC/cm and the breakdown field strength was over 2.0 MV/cm. This result could be explained from the analysis comparing with a standard sample using RBS because the composition of the film deposited at this condition was closest to the stoichiometric $Ta_2$O\ulcorner. The result of XPS analysis convinced that this film was stoichiometric $Ta_2$O\ulcorner film. A maximum cathode voltage was observed when $O_2$gas flow rate was 30 sccm. This shows that the Schiller's proposition that one can obtain stoichiometric films at the condition of maximum cathode voltage is not correct and more oxygen than that of the maximum voltage condition is necessary to deposit the stoichiometric Ta$_2$O\ulcorner films.

• 한국전기전자재료학회논문지
• /
• 제20권1호
• /
• pp.8-13
• /
• 2007

In MIS capacitor structure, we have studied the electrical properties in Ammonium Sulfide solution treatment while AIN thin film as a insulator is being formed by reactive sputtering method. The deposition process conditions of AIN thin film we temperature $250^{\circ}C$, DC Power 150 W, pressure 5 mTorr and 8 sccm(Ar : 4 sccm, $N_{2}$ : 4 sccm). The surface of GaAs was treated with Ammonium Sulfide solution, it was shown the leakage current was less than $10^{-8}\;A/cm^{2}$. The deep depletion phenomena of inverse area with treating Ammonium Sulfide solution in C-V analysis was improved as compared the condition of without Ammonium Sulfide solution and hysteresis property as well.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
• /
• pp.19-21
• /
• 2003

In this paper, we studied on life-decision of underground cable of live-lines state. As all equipments have been wear, underground cables decided design-life on the whole 30 years because underground cable have been occurred aging as time goes. CV cable has been become about 30 years after installation in the South Korea, is come to a important point of time with estimation about life. Study target cable is 22 kV CV cables in this point of view and installation cable is about 10 years before and behind. Measurement method used dc leakage method of live-lines state that applied voltage of 50V in neutral point and data is analyzing result that is measured during 5 years. In this result, insulation resistance could confirm that change according to season and cause is effect of humidity, seasons and load current. Also, according as data is gone aging, insulation resistance by Weibull distribution could confirm functionally its decrease. As a result, the aging speed of cable that water tree is gone could confirm fastness very. Numerical analysis result, cable that water tree is not gone could confirm that life of cable that has passed 10 years remains about $10{\sim}20$ years.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
• /
• pp.13-17
• /
• 2004

The PZT thin films are well-known material that has been widely studied for ferroelectric random access memory (FRAM). We etched the PZT thin films by $CF_4/(Cl_2+Ar)$ plasma and investigated improvement in etching damage by $O_2$ annealing. PZT thin films were etched for 1 min in an ICP using a gas mixture of $Cl_2$(80%)/Ar (20%) with 30% $CF_4$ addition. The etching conditions were fixed at a substrate temperature of $30^{\circ}C$, an rf power of 700 W, a dc-bias voltage of -200 V and a chamber pressure of 2 Pa. To improve the ferroelectric properties of PZT thin films after etching, the samples were annealed for 10 min at various temperatures in $O_2$ atmosphere. After $O_2$ annealing, the remanent polarization, fatigue, and the leakage current were gradually recovered to the characteristics of the as-deposited film, according as the temperature increased.

• 드라이브 ㆍ 컨트롤
• /
• 제13권3호
• /
• pp.15-23
• /
• 2016

The direct-drive servo valve(DDV) is a kind of one-stage valve because the main spool valve is directly driven by the dc motor. Since the DDV structure is simple, it is less expensive, more reliable, and offers a reduced internal leakage and a reduced sensitivity to fluid contamination. The control system of the DDV is highly nonlinear due to a current limiter, a voltage limiter, and the flow-force effect on the spool motion. The shape of the step response of the DDV-control system varies considerably according to the magnitudes of the step input and the load pressure. The system-design requirements mean that the overshoots should be less than 20%, and the errors at 0.02s should be less than 2%, regardless of the reference-step input sizes of 1V and 5V and the load-pressure magnitudes of 0MPa and 20.7MPa. To satisfy the system-design requirements, the PID-controller parameters of $K_c$, $T_i$ and $T_d$, and the derivative-feedback gain of $K_{der}$ are designed using the root locus and manual tuning.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제14권6호
• /
• pp.797-801
• /
• 2014

This research presented the concept of employing the punch-through diode triggered SCRs (PTTSCR) for low voltage ESD applications such as transient voltage suppression (TVS) devices. In order to demonstrate the better electrical properties, various traditional ESD protection devices, including a silicon controlled rectifier (SCR) and Zener diode, were simulated and analyzed by using the TCAD simulation software. The simulation result demonstrates that the novel PTTSCR device has better performance in responding to ESD properties, including DC dynamic resistance and capacitance, compared to SCR and Zener diode. Furthermore, the proposed PTTSCR device has a low reverse leakage current that is below $10^{-12}$ A, a low capacitance of $0.07fF/mm^2$, and low triggering voltage of 8.5 V at $5.6{\times}10^{-5}$ A. The typical properties couple with the holding voltage of 4.8 V, while the novel PTTSCR device is compatible for protecting the low voltage, high speed ESD protection applications. It proves to be good candidates as ultra-low capacitance TVS devices.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
• /
• pp.23-26
• /
• 2003

The BLT thin film and MgO buffer layer were fabricated using a metalorganic decomposition method and the DC sputtering technique. The MgO thin film was deposited as a buffer layer on $SiO_2/Si$ and BLT thin films were used as a ferroelectric layer. The electrical of the MFIS structure were investigated by varying the MgO layer thickness. TEM showsno interdiffusion and reaction that suppressed by using the MgO film as abuffer layer. The width of the memory window in the C-Y curves for the MFIS structure decreased with increasing thickness of the MgO layer Leakage current density decreased by about three orders of magnitude after using MgO buffer layer. The results show that the BLT and MgO-based MFIS structure is suitable for non-volatile memory FETs with large memory window.

• 한국전기전자재료학회논문지
• /
• 제24권12호
• /
• pp.939-943
• /
• 2011

In this paper, reliability of the two sandwiched MIM capacitors of $Al_2O_3-HfO_2-Al_2O_3$ (AHA) and $SiO_2-HfO_2-SiO_2$ (SHS) with hafnium-based dielectrics was analyzed using two kinds of voltage stress; DC and AC voltage stresses. Two MIM capacitors have high capacitance density (8.1 fF/${\mu}m^2$ and 5.2 fF/${\mu}m^2$) over the entire frequency range and low leakage current density of ~1 nA/$cm^2$ at room temperature and 1 V. The charge trapping in the dielectric shows that the relative variation of capacitance (${\Delta}C/C_0$) increases and the variation of voltage linearity (${\alpha}$/${\alpha}_0$) gradually decreases with stress-time under two types of voltage stress. It is also shown that DC voltage stress induced greater variation of capacitance density and voltage linearity than AC voltage stress.

• 한국진공학회지
• /
• 제9권4호
• /
• pp.411-418
• /
• 2000

DC 반응성 스퍼터링법을 이용하여 스퍼터링 가스내 산소함량을 30~70%의 범위에서 변화시키며 상온에서 300 nm 두께의 $Al_2O_3$ 박막을 제조하였다. 스퍼터링 가스내 산소함량 30~70%의 조건에서 모두 비정질 $Al_2O_3$ 박막이 성막되었으며, 스퍼터링 가스내 산소함량에 무관하게 1.58 정도의 굴절계수를 나타내었다. 스퍼터링 가스내 산소함량 50 % 이상의 조건으로 증착한 $Al_2O_3$ 박막은 550 nm 파장에서 98% 정도의 우수한 투과도를 나타내었으나, 산소함량 30% 및 40%의 조건에서는 투과도가 94% 정도로 저하하였다. 스퍼터링 가스내 산소함량 50%의 조건으로 성막한 $Al_2O_3$ 박막의 유전상수는 10.9, 손실계수는 0.01로 최적의 유전특성을 나타내었다. 스퍼터링 가스내 산소함량 40~60%의 조건으로 증착한 $Al_2O_3$박막은 C-V곡선에서 flatband 전압 $V_{FB}$의 이동이 발생하지 않았으며, 150 kV/cm에서 $10^{-5}\textrm{A/cm}^2$ 이하의 우수한 누설전류 특성을 나타내었다.