• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.129-134
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• 2004

The development of fabrication processes of polycrystalline-silicon-thin-film transistors (poly-Si TFTs) at low temperatures is reviewed. Rapid crystallization through laser-induced melt-regrowth has an advantage of formation of crystalline silicon films at a low thermal budget. Solid phase crystallization techniques have also been improved for low temperature processing. Passivation of $SiO_2$/Si interface and grain boundaries is important to achieve high carrier transport properties. Oxygen plasma and $H_2O$ vapor heat treatments are proposed for effective reduction of the density of defect states. TFTs with high performance is reported.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1631-1636
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• 1989

A space charge model for semiconductor reduced gas sensors has been roposed and applied to gas sensing mechanism. SnO2-x and SnO2-x/Pt thin film were deposited by vacuum evaporating method. And Hall effect and gas sensitivity characteristics of these sensors were measured. From the space charge model and carrier concentration, the number of the adsorbed gas atom on the solid surface was calculated quantitatively. The gas sensing model was compared with CO gas sensitivities of the fabricated thin film gas sensors.

• Proceedings of the Korean Magnestics Society Conference
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• 2010.06a
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• pp.79-79
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• 2010

Semimetallic bismuth (Bi) has been extensively investigated over the last decade since it exhibits very intriguing transport properties due to their highly anisotropic Fermi surface, low carrier concentration, long carrier mean free path l, and small effective carrier mass $m^*$. In particular, the great interest in Bi nanowires lies in the development of nanowire fabrication methods and the opportunity for exploring novel low-dimensional phenomena as well as practical application such as thermoelectricity[1]. In this work, we introduce a self-assembled interconnection of nanostructures produced by an on-film formation of nanowires (OFF-ON) method in order to form a highly ohmic Bi nanobridge. A Bi thin film was first deposited on a thermally oxidized Si (100) substrate at a rate of $40\;{\AA}/s$ by radio frequency (RF) sputtering at 300 K. The sputter system was kept in an ultra high vacuum (UHV) of $10^{-6}$ Torr before deposition, and sputtering was performed under an Ar gas pressure of 2m Torr for 180s. For the lateral growth of Bi nanowires, we sputtered a thin Cr (or $SiO_2$) layer on top of the Bi film. The Bi thin films were subsequently put into a custom-made vacuum furnace for thermal annealing to grow Bi nanowires by the OFF-ON method. After thermal annealing, the Bi nanowires cannot be pushed out from the topside of the Bi films due to the Cr (or $SiO_2$) layer. Instead, Bi nanowires grow laterally as a mean s of releasing the compressive stress. We fabricated a self-assembled Bi nanobridge (d=192 nm) device in-situ using OFF-ON through annealing at $250^{\circ}C$ for 10hours. From I-V measurements taken on the Bi nanobridge device, contacts to the nanobridge were found highly ohmic. The quality of the Bi nanobridge was also proved by the high MR of 123% obtained from transverse MR measurements. These results manifest the possibility of self-assembled nanowire interconnection between various nanostructures for a variety of applications and provide a simple device fabrication method to investigate transport properties on nanowires without complex patterning and etching processes.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.5
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• pp.1-7
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• 2007

AZO thin films have been fabricated on quartz substrate with various Al doping concentrations and annealing temperatures by sol-gel method. The bset condition of (002) orientation and smooth surface (rms = 1.082 nm) is obtained for the AZO thin film doped with 1 mol % Al and annealed at 550 $^{\circ}C$. The optical transmittance of AZO thin films is higher than 80 % in the visible region. We observe that the energy band gap extends with increasing the Al doping concentration. This phenomenon is due to the Burstein-Moss effect. Through the measurement of Hall effect, it is observed that the AZO thin film has larger carrier concentration and smaller electrical resistivity than the pure ZnO thin film. However, the AZO thin film shows the decrease of carrier concentration and the increase of resistivity with the increase of Al concentration, that is due to the segregation of Al at grain boundaries. The maximum carrier concentration of $1.80{\times}10^{19}\;cm^{-3}$ and the minimum resistivity of 0.84 ${\Omega}cm$ are obtained for the AZO thin film doped with 1 mol % Al and annealed at 550 $^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.47 no.3
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• pp.262-267
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• 2010

a-SiC has been thought as an ideal candidate for conventional silicon at many applications. However, the uniformity problem of deposition has been a obstacle for conventional use of a-SiC:H films. a-SiC:H films were deposited on (100) silicon wafer by RPECVD system in various temperature. HMDS and $H_2$ gas were used as a precursor and a carrier gas, respectively. The flow rate of HMDS source and $C_2H_2$ dilution gas was fixed in order to study the carbon effect on the film stoichiometric and bonding properties. The plasma power varied from 200 to 400W. We used three types of source delivery line to control the uniformity and film properties of deposited film. We showed that the change of source delivery line has effect on the film uniformity of deposited film and this change of line did not affect on film properties. Also, the change of deposition conditions has effect on the film uniformity.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1783-1786
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• 2007

The copper film coated by Sn is often used in various applications such as LCD, Mobile Phone and etc. Especially, when the film is used as tape carrier package(TCP) of LCD panel, the film is repeatedly applied by mechanical or(and) thermal stress and then is often failed. Therefore, to guarantee the reliability of the electrical devices using the film, the tensile and fatigue characteristics of the film are important. In this study, to obtain the tensile and fatigue characteristics of the film, the specimen was fabricated by etching process to make a smooth specimen of 2000 ${\mu}m$ width, 8000 ${\mu}m$ length and 15.26 ${\mu}m$ thickness. The 2 kinds of specimen were fabricated by other manufacturing process. These specimens had values of Young's modulus(80.2GPa) lower than literature values(108${\sim}$145GPa) for bulk values, but had high values of the yield and ultimate strength as 317MPa and 437MPa, respectively. And fatigue test of load-control with 20Hz frequency was performed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.1
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• pp.102-109
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• 1987

This study is carrier out to investigate the carrier injection and the characteristics of trapping for the CVD deposited Al2O3 film on Si substrates. Samples used are metal -Al2O3-Si Structure in which metal field plates are used with Aluminium or God. Canier injection and trapping, which result in flat band voltalge shift, occur at fields as low as 1~2 MV/cm. An approximate method is proposed for computing the location of the centroid of the trapped electrons in this paper. Results show that carriers are trapped near the injecting interface at fields less than about 5MV/cm. Because of continued charging, a steady state can not be reached. Therefore the unique I-V curve is obtained when the traps are initially empty. By utilization of applied voltage on each point of the fresh device sample, it is measured the I-V surves for two polarities of applied voltage. The current densities observed in the Al2O3 films are much larger than those obtained in SiO2.

• Journal of Information Display
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• v.9 no.3
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• pp.8-11
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• 2008

A novel non-alkoxide sol-gel process for synthesizing Ga-doped ZnO thin film on glass was derived for possible use as a transparent electrode in flat-panel displays, using zinc acetate dehydrate as the starting material. The structural and electrical properties of thin films have been characterized as functions of Ga addition and post-heat-treatments. Their carrier density, Hall mobility, and optical transmittance were measured and discussed herein to explain the characteristics of the sol-gel-derived Ga-doped ZnO thin film on glass.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.289.1-289.1
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• 2016

Germanium (Ge) with higher carrier mobility and a lower crystallization temperature has been considered as the channel material of thin-film transistors for display applications. Various methods were studied for crystallizaion of poly-Ge from amorphous Ge at low temperature. Especially Metal induced crystalliazation (MIC) process was widely studied because low process cost. In this paper, we investigate copper diffusion process of different thick (70 nm, 350 nm) poly-Ge film obtained by MIC process at various temperatures (250, 300, and $350^{\circ}C$) through atomic force microscopy (AFM), Raman spectroscopy, and secondary ion mass spectroscopy (SIMS) measurement. Crystallization completeness and grain size was similar in all the conditions. Copper diffusion profile of 370 nm poly-Ge film show simirly results regardless of process temperature. However, copper diffusion profile of 70 nm poly-Ge film show different results by process temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.582-585
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• 2001

InSb temperature dependent hall effect of multilayerd structures were investigated. According to variation of magnetic field measured hall coefficient, Hall mobility, carrier density and hall voltage. For the measurement of electrical properties of hall device, evaperated InSb thin film fabricated with series and parallel multilayers. We found that the XRD analysis of InSb thin film showed good properties at 200$^{\circ}C$, 60 minutes. Resistance of ohmic contact increased linearly due to increasing current. Some of device fabrication technique and analysis of Hall effect were discussed.