• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.88-91
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• 2000

The $(Sr_{0.85}Ca_{0.15})TiO_3$(SCT) thin films are deposited on Pt-coated electrode(Pt/TiN/$SiO_2$/Si) using RF sputtering method. The crystallinity of SCT thin films is increased with increase of substrate temperature in the temperature range of 200~500$[^{\circ}C]$. V-I characteristics of SCT thin films show the increasing leakage current with the increases of deposition temperature. The conduction mechanism of the SCT thin films observed in the temperature range of 25~100$[^{\circ}C]$ can be divided into four characteristic regions with different mechanism by the increasing current.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1030-1033
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• 2002

ZnO thin films on (100)p-type silicon substrates have been deposited by pulsed laser deposition(PLD) technique using an Nd:YGA laser with a wavelength of 266nm. The influence of the deposition parameters, such as oxygen pressure, substrate temperature and laser energy density variation on the properties of the grown film, was studied. The experiments were performed for substrate temperatures in the range of $200{\sim}500^{\circ}C$ and oxygen pressure in the range of $10^{-2}{\sim}10^2mTorr$. We investigated the structural, morphological and optical properties of ZnO thin films using X-ray diffraction(XRD), atomic force microscopy(AFM), photoluminescence(PL).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.152-155
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• 1996

Platinum thin films were deposited on $Al_2$O$_3$substrate by DC magnetron sputtering for RTD(Resistance Thermometer Devices) temperature sensors. We made Pt resistance pattern on $Al_2$O$_3$substrate by lift-off method and fabricated Pt-RTD temperature sensors by using W-wire, silver epoxy and SOG(spin-on-glass). In the temperature range of 25~40$0^{\circ}C$, we investigated TCR(temperature coefficient of resistance) and resistance ratio of Pt-RTD temperature sensors. TCR values were increased with increasing the annealing temperature, time and the thickness of Pt thin films. Resistance values were varied lineally within the range of measurement temperature. At annealing temperature of 100$0^{\circ}C$, annealing time of 240min and thin film thickness of 1${\mu}{\textrm}{m}$, we obtained Pt-RDT TCR value of 3825ppm/$^{\circ}C$ closed to the Pt bulk value.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1568-1570
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• 2009

Nanocrystalline silicon thin films were deposited using an internal-type inductively coupled plasma-chemical vapor deposition at room temperature by varying the bias power to the substrate and the structural characteristics of the deposited thin film were investigated. The result showed that the crystalline volume fraction was decreased with the increase of bias power. At the low bias power range of 0~60 W, the compress stress in the deposited thin film was in the range of -34 ~ -77 Mpa which is generally lower than the residual stress observed for the nanocrystalline silicon thin films deposited by capacitively coupled plasma.

• Journal of the Korean Ceramic Society
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• v.31 no.4
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• pp.436-447
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• 1994

ZnO transparent conducting thin film, which is a strong candidate for a transparent electrical contact in optoelectronic devices, was prepared by the vapour spraying method on the slide glass in nitrogen ambient at the atmospheric pressure. The structural, optical and electrical properties of films show a strong dependence on substrate temperature, and the optimum range of deposition temperature existed to obtain TCO(Transparent Conducting Oxide) films. At the higher temperatures, milky films were obtained. In such optimum range, the bandgap in ZnO films was determined from the spectral dependence of absorption coefficient and electrical characteristics were characterized with by the Hall mobility and carrier concentration.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.1
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• pp.49-57
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• 2002

Including RF Package inductance, substrate coupling through conductive silicon(Si)-substrate is modeled and quantitatively characterized. 2-port substrate coupling model is extended for the characterization of multi-port substrate coupling between digital circuit block and analog/RF circuit block. Furthermore, scalable parameter extraction model is developed. Multi-port substrate coupling can be investigated by linearly superposing a frequency-dependent 2-port substrate coupling model using scalable parameters. In addition, Substrate coupling including RF package inductance effect is quantitatively investigated. It is shown that package effect increases substrate coupling and shifts a characteristic frequencies(i.e., poles) to the higher frequency range. The proposed methodology can be efficiently used to the mixed-signal circuit performance verification.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.146-147
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• 2011

Processing a large area substrate for liquid crystal display (LCD) or solar panel applications in a capacitively coupled plasma (CCP) reactor is becoming increasingly challenging because of the size of the substrate size is no longer negligible compared to the wavelength of the applied radio frequency (RF) power. The situation is even worse when the driving frequency is increased to the Very High Frequency (VHF) range. When the substrate size is still smaller than 1/8 of the wavelength, one can obtain reasonably uniform process results by utilizing with methods such as tailoring the precursor gas distribution by adjustingthrough shower head hole distribution or hole size modification, locally adjusting the distance between the substrate and the electrode, and shaping shower head holes to modulate the hollow cathode effect modifying theand plasma density distribution by shaping shower head holes to adjust the follow cathode effect. At higher frequencies, such as 40 MHz for Gen 8.5 (2.2 m${\times}$2.6 m substrate), these methods are not effective, because the substrate is large enough that first node of the standing wave appears within the substrate. In such a case, the plasma discharge cannot be sustained at the node and results in an extremely non-uniform process. At Applied Materials, we have studied several methods of modifying the standing wave pattern to adjusting improve process non-uniformity for a Gen 8.5 size CCP reactor operating in the VHF range. First, we used magnetic materials (ferrite) to modify wave propagation. We placed ferrite blocks along two opposing edges of the powered electrode. This changes the boundary condition for electro-magnetic waves, and as a result, the standing wave pattern is significantly stretched towards the ferrite lined edges. In conjunction with a phase modulation technique, we have seen improvement in process uniformity. Another method involves feeding 40 MHz from four feed points near the four corners of the electrode. The phase between each feed points are dynamically adjusted to modify the resulting interference pattern, which in turn modulate the plasma distribution in time and affect the process uniformity. We achieved process uniformity of <20% with this method. A third method involves using two frequencies. In this case 40 MHz is used in a supplementary manner to improve the performance of 13 MHz process. Even at 13 MHz, the RF electric field falls off around the corners and edges on a Gen 8.5 substrate. Although, the conventional methods mentioned above improve the uniformity, they have limitations, and they cannot compensate especially as the applied power is increased, which causes the wavelength becomes shorter. 40 MHz is used to overcome such limitations. 13 MHz is applied at the center, and 40 MHz at the four corners. By modulating the interference between the signals from the four feed points, we found that 40 MHz power is preferentially channeled towards the edges and corners. We will discuss an innovative method of controlling 40 MHz to achieve this effect.

• ETRI Journal
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• v.25 no.2
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• pp.65-72
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• 2003

To achieve cost and size reductions, we developed a low cost manufacturing technology for RF substrates and a high performance passive process technology for RF integrated passive devices (IPDs). The fabricated substrate is a conventional 6" Si wafer with a 25${\mu}m$ thick $SiO_2$ surface. This substrate showed a very good insertion loss of 0.03 dB/mm at 4 GHz, including the conductive metal loss, with a 50 ${\Omega}$ coplanar transmission line (W=50${\mu}m$, G=20${\mu}m$). Using benzo cyclo butene (BCB) interlayers and a 10 ${\mu}m$ Cu plating process, we made high Q rectangular and circular spiral inductors on Si that had record maximum quality factors of more than 100. The fabricated inductor library showed a maximum quality factor range of 30-120, depending on geometrical parameters and inductance values of 0.35-35 nH. We also fabricated small RF IPDs on a thick oxide Si substrate for use in handheld phone applications, such as antenna switch modules or front end modules, and high-speed wireless LAN applications. The chip sizes of the wafer-level-packaged RF IPDs and wire-bondable RF IPDs were 1.0-1.5$mm^2$ and 0.8-1.0$mm^2$, respectively. They showed very good insertion loss and RF performances. These substrate and passive process technologies will be widely utilized in hand-held RF modules and systems requiring low cost solutions and strict volumetric efficiencies.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.106-107
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• 2009

In this study, We investigated the effects of substrate temperature on the electrical and optical properties of Ga-, B-codoped ZnO(GZOB) thin films. GZOB thin films were deposited on glass substrate with various substrate temperature in the range from R.T. to $500\;^{\circ}C$ by DC magnetron sputtering. In the reslt, GZOB films at $400\;^{\circ}C$ exhibited a low resistivity value of $8.67\;{\times}\;10^{-4}\;{\Omega}-cm$, and a visible transmission of 80% with a thickness of 300 nm. This result indicated that the addition of Ga and B in ZnO films leads to the improvement of conductivity and transparent. From the result, we can confirm the possibility of the application as transparent conductive electrodes.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.687-694
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• 2006

We report on the fabrication of organic-based flexible displays using an amorphous IZO anode grown at room temperature. The IZO anode films were grown by a conventional DC reactive sputtering on the polycarbonate (PC) substrate at room temperature using a synthesized IZO target in a $Ar/O_2$ ambient. Both x-ray diffraction (XRD) and high resolution electron microscope (HREM) examination results show that the IZO anode film grown at room temperature Is complete amorphous structure due to low substrate temperature. A sheet resistance of $35.6\Omega/\Box$, average transmittance above 90 % in visible range, and root mean spare roughness of $6\sim10.5\AA$ were obtained even in the IZO anode film grown on PC substrate at room temperature. It is shown that the $Ir(ppy)_3$ doped flexible organic light emitting diode (OLED) fabricated on the IZO anode exhibit comparable current-voltage-luminance characteristics as well as external quantum efficiency and power efficiency to OLED fabricated on conventional ITO/Glass substrate. These findings indicate that the IZO anode film grown on PC substrate is a promising anode materials for the fabrication of organic based flexible displays.