• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.2
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• pp.115-118
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• 2017

Highly photosensitive and wide bandgap amorphous silicon oxide (a-$SiO_x$:H) films were developed at low temperature ranges ($100{\sim}150^{\circ}C$) with employing plasma-enhanced chemical vapor deposition by optimizing $H_2/SiH_4$ gas ratio and $CO_2$ flow. Photosensitivity more than $10^5$ and wide bandgap (1.81~1.85 eV) properties were used for making the a-$SiO_x$:H thin film solar cells, which exhibited a high open circuit voltage of 0.987 V at the substrate temperature of $100^{\circ}C$. In addition, a power conversion efficiency of 6.87% for the cell could be improved up to 7.77% by employing a new n-type nc-$SiO_x$:H/ZnO:Al/Ag triple back-reflector that offers better short circuit currents in the thin film photovoltaic devices.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.339.1-339.1
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• 2014

In this paper we studied the application of inter-poly dielectric as silicon dioxide-like film was deposited by the higher energy assisting deposition (HEAD) process the modified CCP process, which enables low temperature (LT) process and improving film density. In these experiments the relative hydrogen concentration of $SiO_2$-like films deposited on silicon substrate were analyzed by the secondary ion mass spectroscopy (SIMS) and it was shown that our lower hydrogenated oxide (LHO) film prepared by HEAD process with the precursor contained the siloxane species had lower hydrogen concentration, $8{\times}10{\cdot}^{22}cm{\cdot}^3$ than that of the commercial undoped silicon glass (USG) film ($1{\times}10{\cdot}^{21}cm{\cdot}^3$) prepared by the high density plasma-chemical vapor deposition (HDP-CVD). We consider that the LHO film deposited by HEAD process used as high performance material into Flash memory devices.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.351.2-351.2
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• 2014

Indium tin oxide (ITO) has a lot of variations of its properties because it is basically in an amorphous state. Therefore, the differences in composition ratio of ITO can result in alteration of electrical properties. Normally, ITO is considered as transparent conductive oxide (TCO), possessing excellent properties for the optical and electrical devices. Quantitatively, TCO has transparency over 80 percent within the range of 380nm to 780nm, which is visible light although its specific resistance is less than $10-3{\Omega}/cm$. Thus, the solar cell is the best example for which ITO has perfectly matching profile. In addition, when ITO is used as transparent conductive electrode, this material essentially has to have a proper work function with contact materials. For instance, heterojunction with intrinsic thin layer (HIT) solar cell could have both front ITO and backside ITO. Because each side of ITO films has different type of contact materials, p-type amorphous silicon and n-type amorphous silicon, work function of ITO has to be modified to transport carrier with low built-in potential and Schottky barrier, and approximately requires variation from 3 eV to 5 eV. In this study, we examine the change of work function for different sputtering conditions using ultraviolet photoelectron spectroscopy (UPS). Structure of ITO films was investigated by spectroscopic ellipsometry (SE) and scanning electron microscopy (SEM). Optical transmittance of the films was evaluated by using an ultraviolet-visible (UV-Vis) spectrophotometer

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1528-1530
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• 1997

As device size shrinks, contamination will increasingly affect the reliability and yield of device. Therefore, contaminants must be removed from the surfaces of Si wafers prior to each process. But it becomes out increasingly difficult to clean silicon surfaces with finer patterns by the conventional wet treatment because of the viscosity and surface tension of solutions. Hence, a damage less dry cleaning process is needed for the silicon surfaces. For the removal of Si native oxide by UV-enhanced dry cleaning. $F_2$ gas and $F_2/H_2$ mixed gas were applied. As a result of analysis, UV-enhnaced $F_2/H_2$ treatment is more suitable than UV-enhanced $F_2$ treatment for removal of native oxide on the surfaces of Si wafers.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.5
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• pp.504-509
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• 1999

In-situ cleaning and subsequent silicon epitaxial film growth were performed in a load-locked reactor equipped with Hg-grid UV lamp and PBN heater to obtain the smooth and contaminant-free underlying surface and develop low-temperature epitaxial film growth process. The removals of organic and native oxide were investigated using UV-excited $O_2$ and $NF_{3}/H_{2}$, and the effect of the surface condition was examined on the quality of silicon epitaxial film grown at temperature as low as $750^{\circ}C$. UV-excited gas phase cleaning was found to be effective in removing the organic and native oxide successfully providing a smooth surface with RMS roughness of 0.5$\AA$ at optimal condition. Crystalline quality of epitaxial film was determined by smoothness of cleaned surface and the presence of native oxide and impurity. Crystalline defects such as dislocation loops or voids due to the surface roughness were observed by XTEM.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.389-392
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• 2009

Metal oxides have been proposed as an alternative channel material to hydrogenated amorphous silicon in thin film transistors (TFTs) because their higher mobility and stability make them suitable for transistor active layers. Thin films of indium zinc oxide (IZO) were deposited using a High Target Utilization Sputtering (HiTUS) system on various dielectrics, some of which were also deposited with the HiTUS. Investigations into bottom-gated IZO TFTs have found mobilities of 8 $cm^2V\;^1s^{-1}$ and switching ratios of $10^6$. There is a variation in the threshold voltage dependent on both oxygen concentration, and dielectric choice. Silica, alumina and silicon nitride produced stable TFTs, whilst hafnia was found to break down as a result of the IZO.

• The Korean Journal of Ceramics
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• v.5 no.2
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• pp.142-147
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• 1999

The interaction between commercial $Si_3N_4$ powder and two types of additives (nitrate and oxide additives) during the sintering of $Si_3N_4$ was investigated. The nitrates solution or oxide particles were added as a sintering additives. The surface of mixed powder was observed with FT-IR, TG, and HREM. DTA was used to characterize the reactivity of the powders. The formation of crystalline phases and phase transformation were analyzed by XRD. The adsorption of the additives on the surface of silicon nitride was confirmed in the nitrate salts. It was shown that the adsorption occurred by interaction between the amorphous $SiO_2$ layer on the $Si_3N_4$ surface and metal cations $(Al^{3++\; and \;Y^{3+})$ and anions $(NO_3\;^-\; or\; OH^-)$, resulting in a higher degree of homogeneous distribution of additives.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.7
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• pp.713-717
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• 2004

In this study, the etched trench properties including cross-sectional profile, surface roughness, and crystalline defects were investigated depending on the various silicon etching and additive gases, For the case of HBr$He-O_2SiF_4$ trench etching gas mixtures, the excellent trench profile and minimum defects in the silicon trench were achieved. Due to the residual oxide film grown by the additive oxygen gas, which acts as a protective layer during trench etching, the undercut and defects generation in the trench were suppressed. To improve the electrical characteristics of trench gate, the hydrogen annealing process after trench etching was also adopted. Through the hydrogen annealing, the trench corners might be rounded by the silicon atomic migration at the trench corners having high potential. The rounded trench corner can afford to reduce the gate electric field and grow a uniform gate oxide. As a result, dielectric strength and TDDB characteristics of the hydrogen annealed trench gate oxide were remarkably increased compared to the non-hydrogen annealed one.

• Journal of the Korean Vacuum Society
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• v.1 no.1
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• pp.153-161
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• 1992

A plasma has been used in a high vaccum, cold wall reactor for low temperature deposition of C54 TiSi2 and for in-situ surface cleaning prior to silicide deposition. SiH4 and TiCl4 were used as the silicon and titanium sources, respectively. The deposited films had low resistivities in the range of 15~25 uohm-cm. The investigation of the experimental variables' effects on the growth of silicide and its concomitant silicon consumption revealed that and were the dominant species for silicide formation and the primary factors in silicon consumption were gas composition ratio and temperature. Increasing silane flow rate from 6 to 9 sccm decreased silicon consumption from 1500 A/min to less than 30 A/min. Furthermore, decreasing the temperature from 650 to $590^{\circ}C$ achieved blanket silicide deposition with no silicon consumption. A kinetic model of silicon consumption is proposed to understand the fundamental mechanism responsible for the dependence of silicon consumption on SiH4 flow rate.

• Journal of the Semiconductor & Display Technology
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• v.4 no.3 s.12
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• pp.1-4
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• 2005

Silicon oxynitride films were deposited using ammonia as a nitrogen source via PECVD (plasma enhanced chemical vapor deposition) to study the physical properties of the films. Silane and nitrous oxide were used as silicon and oxygen sources, respectively. The composition of the silicon oxynitride films was well controlled by changing the ratios of the sources and confirmed by XPS. The silicon oxynitride films with high oxygen content showed bigger compressive stress and less refractive index, while the values of surface roughness were around 1 nm, irrespective of the variation of the source ratios.