• Journal of Power Electronics
• /
• v.15 no.2
• /
• pp.530-543
• /
• 2015

Air-cooling method is adopted on the basis of the requirements for the thermal stability and convenient field use of an electrical source transmitter. The power losses of the transmitter are determined after calculating the losses of the alternating current (AC)-direct current (DC) power supply, the constant-current circuit, and the output circuit. According to the analysis of the characteristics of a heat sink with striped fins and a fan, the engineering calculation expression of the Nusselt number and the design process for air-cooled dissipation are proposed. Experimental results verify that the error between calculated and measured values of the transmitter losses is 12.2%, which meets the error design requirements of less than 25%. Steady-state average temperature rise of the heat sink of the AC-DC power supply is $22^{\circ}C$, which meets the design requirements of a temperature rise between $20^{\circ}C$ and $40^{\circ}C$. The transmitter has favorable thermal stability with 40 kW output power.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.2
• /
• pp.86-90
• /
• 2017

This work reports the phase-change behavior and thermal stability of doped GeSbTe/GeSbTe bilayers. We prepared the bilayers using RF sputtering, and annealed them at annealing temperature ranging from $100^{\circ}C$ to $400^{\circ}C$. The sheet resistance of the bilayer decreased and saturated with increasing annealing temperature, and the saturated value was close to that of pure GeSbTe film. The surface of the bilayer roughened at $400^{\circ}C$, which corresponds to the surface roughening of doped GeSbTe film. Mixed phases of face-centered cubic and hexagonal close-packed crystalline structures were identified in the bilayers annealed at elevated temperature. These results indicate that the phase-change behavior of the bilayer depends on the concurrent phase-transitions of the two GeSbTe-based films. The dopants in the doped GeSbTe film were diffused out at annealing temperatures of $300^{\circ}C$ or higher, which implies that the thermal stability of the bilayer should be considered for its application in phase-change electronic devices.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.6
• /
• pp.487-490
• /
• 2007

In this paper, the formation and thermal stability characteristics of Ni silicide using Ni-V alloy on Boron cluster ($B_{18}H_{22}$) implanted bulk and SOI substrate were examined in comparison with pure Ni for nano-scale CMOSFET. The Ni silicide using Ni-V alloy on $B_{18}H_{22}$ implanted SOI substrate after high temperature post-silicidation annealing showed the lower sheet resistance, no agglomeration interface image and lower surface roughness than that using pure Ni. The thermal stability of Ni silicide was improved by using Ni-V alloy on $B_{18}H_{22}$ implanted SOI substrate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.19 no.11
• /
• pp.1000-1004
• /
• 2006

In this paper, thermal stability of Ni-silicide formed on the SOI substrate with $B_{11}$ has been characterized. The sheet resistance of Ni-silicide on un-doped SOI and $B_{11}$ implanted bulk substrate was increased after the post-silicidation annealing at $700^{\circ}C$ for 30 min. However, in case of $B_{11}$ implanted SOI substrate, the sheet resistance showed stable characteristics after the post-silicidation annealing up to $700^{\circ}C$ for 30 min. The main reason of the excellent property of $B_{11}$ sample is believed to be the retardation of Ni diffusion by the boron and bottom oxide layer of SOI. Therefore, retardation of Ni diffusion is highly desirable lot high performance Ni silicide technology.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.51 no.5
• /
• pp.185-190
• /
• 2002

Capacitor material utilized in the downsizing passive devices and dynamic random access memory(DRAM) requires the physical and electrical properties at given area such as capacitor thickness reduction, relative dielectric constant increase, low leakage current and thermal stability. Common capacitor materials, $SiO_2$, $Si_3N_4$, $SiO_2$/$Si_3N_4$,TaN and et al., used until recently have reached their physical limits in their application to several hundred angstrom scale capacitor. $Ta_2O_{5}$ is known to be a good alternative to the existing materials for the capacitor application because of its high dielectric constant (25 ~35), low leakage current and high breakdown strength. Despite the numerous investigations of $Ta_2O_{5}$ material, there have little been established the clear understanding of the annealing effect on capacitance characteristic and conduction mechanism, design and fabrication for $Ta_2O_{5}$ film capacitor. This study presents the structure-property relationship of reactive-sputtered $Ta_2O_{5}$ MIM capacitor structure processed by annealing in a vacuum. X-ray diffraction patterns skewed the existence of amorphous phase in as-deposited condition and the formation of preferentially oriented-$Ta_2O_{5}$ in 670, $700^{\circ}C$ annealing. On 670, $700^{\circ}C$ annealing under the vacuum, the leakage current decrease and the enhanced temperature-capacitance characteristic stability. and the leakage current behavior is stable irrespective of applied electric field. The results states that keeping $Ta_2O_{5}$ annealed at vacuum gives rise to improvement of electrical characteristics in the capacitor by reducing oxygen-vacancy and the broken bond between Ta and O.

• The Korean Journal of Ceramics
• /
• v.3 no.2
• /
• pp.92-95
• /
• 1997

Because of the novel characteristics such as chemical stability, hardness, electrical resistivity and thermal conductivity, diamond-like carbon (DLC) film is a suitable material for the passivation layers. For this purpose, using the PECVD, DLC films were synthesized at room temperature. The adhesion and the hardness of the DLC films deposited on Si an SiO2 substrate were measured. The resistivity of 5.3$\times$$10^8$$\Omega$.cm was measured by automatic spreading resistance probe analysis method. The thermal conductivities of different DLC films were measured and compared with that of phospho silicate glass (PSG) film which is commonly used as passivation layers. The thermal conductivity of DLC film was improved by increasing hydrogen flow rate up to 90 sccm and was better than that of PSG film. The patterning techniques of the DLC film developed using the RIE and the lift-off method to form 5$\mu\textrm{m}$ line. Finally, the thermal characteristics of the power transistor with the DLC film as passiviation layer was analyzed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.06a
• /
• pp.24-25
• /
• 2006

In this study, Ni silicide on the SOI substrate doped B11 is proposed to improve thermal stability. The sheet resistance of Ni-silicide utilizing pure SOI substrate increased after the post-silicidation annealing at $600^{\circ}C$ for 30 min. However, using the proposed B11 implanted substrate, the sheet resistance showed stable characteristics after the post-silicidation annealing up to $700^{\circ}C$ for 30 min.

• Transactions on Electrical and Electronic Materials
• /
• v.6 no.2
• /
• pp.73-77
• /
• 2005

In this study, we investigated response characteristics of liquid crystal display (LCD) with different operating mode of nematic liquid crystals (NLCs) such as 45 $^{circ} twisted nematic (TN), 67.3 $^{circ} TN and electrical controlled birefringence (ECB) on the rubbed polyimide (PI) surface with side chains. The pretilt angles generated on polyimide surfaces of the three kinds of LCD operating modes were about 12 $^{circ} that was higher than those of conventional TN-LCOs. Also, the Electro-optical (EO) performance of these LCOs showed stable condition. Low transmittance of the 45 $^{circ} TN and 67.3 $^{circ} TN cell on the rubbed PI surface were measured by using low cell gap d. The fast response time in ECB cell among the three kinds of LCD operating modes was achieved. Also, thermal ability of fast 90 $^{circ} TN-LCD was investigated. The threshold voltage and the response time of thermal stressed TN-LCOs showed the same performances on no thermal stressed TN-LCOs. There was little change of value in these TN cells. However, the transmittances of TN-LCOs on the rubbed PI surface decreased while increasing thermal stress time. Therefore, the thermal stability of TN-LCD was decreased by the high thermal stress for the long duration.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.27 no.1
• /
• pp.27-32
• /
• 2014

In this paper, PZT piezoelectric ceramic specimens with 4 compositions (Zr/Ti=50/50, 53/47, 56/44, 58/42) in $Pb(Zr,Ti)O_3$ system were fabricated. We studied effects of poling strength and thermal aging on the temperature characteristics of eletromechanical coupling factor k31 of the specimens, which were poled with the DC electric fields, 1.5, 2.5 and 3.5 kV/mm respectively and thermally aged for an hour at $200^{\circ}C$. The eletromechanical coupling factor k31 of the specimen with the composition Zr/Ti= 53/47, nearest to the morphotropic phase boundary decreased the most greatly, irrelevant to the intensity of poling field, due to 1st thermal aging. And the temperature coefficient of eletromechanical coupling factor k31 was (-) in the tetragonal phase composition and (+) in the rhombohedral phase composition, which is reverse in the temperature coefficient of resonance frequency. It is interesting that eletromechanical coupling factor k31 of PZT ceramics is shown to be able to increase as temperature increase in the interval $-20{\sim}80^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 1996.11a
• /
• pp.421-424
• /
• 1996

Effects of humidity absorbing deterioration on AC dielectric breakdown characteristics of modified epoxy resin system with SN(succinonitrile) were investigated. As the forced humidity absorbing deterioration proceeded under high temperature and humidify, glass transition temperature increased. The dielectric breakdown strength increased and then decreased at deterioration cycles higher than 2. Not only, the increment of thermal stability but also, the physical detects such as Internal cracks and voids occurred during the humidity absorbing deterioration cycle were the main causes of the change in dielectric properties.