• 한국전기전자재료학회논문지
• /
• 제19권1호
• /
• pp.71-74
• /
• 2006

In this paper, we investigated the characterization of silicon oxide(SiOx) thin film on Ethylene Terephthalate(PET) substrates by e-beam deposition for transparent barrier application. The temperature of chamber increases from $30^{\circ}C$ to $110^{\circ}C$, the roughness increase while the Water vapor transmission rate (WVTR) decreases. Under these conditions, the WVTR for PET can be reduced from a level of $0.57 g/m^2/day$ (bare subtrate) to $0.05 g/m^2/day$ after application of a 200-nm-thick $SiO_2$ coating at 110 C. A more efficient way to improve permeation of PET was carried out by using a double side coating of a 5-${\mu}m$-thick parylene film. It was found that the WVTR can be reduced to a level of $-0.2 g/m^2/day$. The double side parylene coating on PET could contribute to the lower stress of oxide film, which greatly improves the WVTR data. These results indicates that the $SiO_2$ /Parylene/PET barrier coatings have high potential for flexible organic light-emitting diode(OLED) applications.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 하계학술대회 논문집
• /
• pp.565-568
• /
• 2000

This paper describes on the temperature characteristics of a SDB(silicon-wafer direct bonding) SOI(silicon-on-insulator) Hall sensor. Using the buried oxide $SiO_2$ as a dielectrical isolation layer, a SDB SOI Hall sensor without pn junction isolation has been fabricated on the Si/$SiO_2$/Si structure. The Hall voltage and the sensitivity of the implemented SOI Hall sensor show good linearity with respect to the applied magnetic flux density and supplied current. In the temperature range of 25 to $300^{\circ}C$, the shifts of TCO(temperature coefficient of the offset voltage) and TCS(temperature coefficient of the product sensitivity) are less than $\pm 6.7$$\times$$10^{-3}$/$^{\circ}C$ and $\pm 8.2$$\times$$10^{-4}$/$^{\circ}C$respectively. These results indicate that the SDB SOI structure has potential for the development of a silicon Hall sensor with a high-sensitivity and hip high-temperature operation.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2007년도 추계학술대회 논문집
• /
• pp.9-10
• /
• 2007

In this paper, Thin films of $HfO_2$/Hf were deposited on p-type wafer by Atomic Layer Deposition(ALD). And we studied the electrical characterization of $HfO_2$/Hf/Si MOS capacitor depending on thickness of Hf metal layer. $HfO_2$ films were deposited using TEMAH and $O_3\;at\;350^{\circ}C$. Samples were then annealed using furnace heating to $500^{\circ}C$. The MOS capacitor of round-type was fabricated on Si substrates. Through TEM(Transmission Electron Microscope), XRD(X-ray Diffraction), capacitance-voltage(C-V) and current-voltage(I-V) analysis, the role of thin Hf metal layer for the better $HfO_2$/Si interface property was investigated.

• 대한기계학회논문집A
• /
• 제24권12호
• /
• pp.2909-2916
• /
• 2000

6.5wt% Si steel is widely known as an excellent magnetic material because its magnetostriction is nearly zero. The AX magnetic properties as magnetostriction of 6.5% Si steel were evaluated and compared with those of conventional 3% Si steel sheet. In this paper, the fracture behavior of the poly crystals and single crystals of Fe-6.5wt%Si alloy has been observed. Single crystals were prepared by Floating Zone(FZ) method, which melts the alloy by the use of high temperature electron beam in pure argon gas condition. And the single crystals were annealed at 500$^{\circ}C$ and 700$^{\circ}C$ respectively and tensile tested at room temperature. According to the result, B2 phase has more good elongation than DO$_3$ phase. It was also found that the fracture surfaces of the single crystals have hairline facets in same direction, and the facets change the direction according to the single crystal phase.

• 한국전기전자재료학회논문지
• /
• 제29권6호
• /
• pp.321-326
• /
• 2016

Minimizing the carrier recombination and electrical loss through surface passivation is required for high efficiency c-Si solar cell. Usually, $SiN_X$, $SiO_X$, $SiON_X$ and $AlO_X$ layers are used as passivation layer in solar cell application. Silicon oxide layer is one of the good passivation layer in Si based solar cell application. It has good selective carrier, low interface state density, good thermal stability and tunneling effect. Recently tunneling based passivation layer is used for high efficiency Si solar cell such as HIT, TOPCon and TRIEX structure. In this paper, we focused on silicon oxide grown by various the method (thermal, wet-chemical, plasma) and passivation effect in c-Si solar cell.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
• /
• pp.374-375
• /
• 2006

This paper describes anodic bonding characteristics of MCA to Si-wafer using evaporated Pyrex #7740 glass thin-films for MEMS applications. Pyrex #7740 glass thin-films with the same properties were deposited on MCA under optimum RF sputter conditions (Ar 100 %, input power $1\;W/cm^2$). After annealing at $450^{\circ}C$ for 1 hr, the anodic bonding of MCA to Si-wafer was successfully performed at 600 V, $400^{\circ}C$ in $110^{-6}$ Torr vacuum condition. Then, the MCA/Si bonded interface and fabricated Si diaphragm deflection characteristics were analyzed through the actuation and simulation test. It is possible to control with accurate deflection of Si diaphragm according to its geometries and its maximum non-linearity being 0.05-0.08 %FS. Moreover, any damages or separation of MCNSi bonded interfaces did not occur during actuation test. Therefore, it is expected that anodic bonding technology of MCNSi-wafers could be usefully applied for the fabrication process of high-performance piezoelectric MEMS devices.

• 한국태양에너지학회 논문집
• /
• 제33권2호
• /
• pp.11-17
• /
• 2013

Silicon nitride($SiN_x:H$) deposited by radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) is commonly used for anti-reflection coating and passivation in crystalline silicon solar cell fabrication. In this paper, characteristics of the deposited silicon nitride was studied with change of working pressure, deposition temperature, gas ratio of $NH_3$ and $SiH_4$, and RF power during deposition. The deposition rate, refractive index and effective lifetime were analyzed. The (100) p-type silicon wafers with one-side polished, $660-690{\mu}m$, and resistivity $1-10{\Omega}{\cdot}cm$ were used. As a result, when the working pressure increased, the deposition rate of SiNx was increased while the effective life time for the $SiN_x$-deposited wafer was decreased. The result regarding deposition temperature, gas ratio and RF power changes would be explained in detail below. In this paper, the optimized condition in silicon nitride deposition for silicon solar cell was obtained as 1.0 Torr for the working pressure, $400^{\circ}C$ for deposition temperature, 500 W for RF power and 0.88 for $NH_3/SiH_4$ gas ratio. The silicon nitride layer deposited in this condition showed the effective life time of > $1400{\mu}s$ and the surface recombination rate of 25 cm/s. The crystalline silicon solar cell fabricated with this SiNx coating showed 18.1% conversion efficiency.

• 전력전자학회논문지
• /
• 제24권6호
• /
• pp.459-462
• /
• 2019

This work presents methods for reducing overshoot voltages across the drain-source of silicon carbide (SiC) MOSFETs in grid-connected hybrid active neutral-point-clamped (ANPC) inverters. Compared with 3-level NPC-type inverter, the hybrid ANPC inverter can realize the high efficiency. However, SiC MOSFETs conduct its switching operation at high frequencies, which cause high overshoot voltages in such devices. These overshoot voltages should be reduced because they may damage switching devices and result in electromagnetic interference (EMI). Two major strategies are used to reduce the overshoot voltages, namely, adjusting the gate resistor and using a snubber capacitor. In this paper, advantages and disadvantages of these methods will be discussed. The effectiveness of these strategies is verified by experimental results.

• 한국기계가공학회지
• /
• 제15권3호
• /
• pp.36-43
• /
• 2016

Carbon fiber-reinforced silicon carbide (Cf-SiC) and SiC / SiC composites have high thermal conductivity, and excellent corrosion and wear resistance, a low coefficient for thermal expansion and are lightweight. This is why they are commonly used in parts of the aerospace industry to develop an aircraft thrust deflector, jet vane, combustion chamber, elevens, body flap, and a shingle. So, understanding how this state-of-the-art Cf-SiC affects both internal and external crack detection and determining issues during the manufacturing process of composite materials, should be evaluated according to valuation techniques in the external environment. In this paper, we apply a non-contact air ultrasonic technique of non-destructive testing techniques to perform a study on internal defect detection identification and assessment of carbon-fiber reinforced silicon carbide composites to perform basic research and applied research.

• 비파괴검사학회지
• /
• 제14권2호
• /
• pp.90-100
• /
• 1994

초음파의 속도는 재료의 성질 연구에 폭넓게 사용되고 있다. 본 논문에서는 탄화규소(SiC)와 같은 구조용 세라믹스에서 기공으로 인한 밀도 변화를 미시역학 모델과 초음파의 속도 측정으로부터 결정할 수 있는 비파괴 평가법을 연구하였다. 기공의 특성은 재료의 탄성계수에 민감한 영향을 미치며, 따라서 제시한 미시역학 모델은 기공의 모양과 방향을 모두 고려할 수 있으며, 또한 기공 사이의 상호 작용을 반영하므로 기공량이 높은 경우에도 적용이 가능하다. 이론 밀도의 약 85-100% 밀도를 가진 SiC 시편들의 초음파 속도를 접촉식, 펄스겹침법(pulse overlap method)을 이용하여 측정하였으며, 속도-밀도 (또는 기공) 사이에 좋은 선형 관계가 있는 것으로 나타났다. 측정한 종파 또는 횡파 속도값과 모델로부터 기공의 부피 분율과 밀도를 계산하는 절차를 소개하였으며, 계산한 밀도값은 아르키메데스의 방법으로 측정한 값과 잘 일치하였다.