• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.361-364
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• 2004

Surface doped SOI RESURF LDMOSFET with recessed source region is proposed to improve the on- and off-state characteristics. Surface region of the proposed LDMOS structure is doped like step. The characteristics of the proposed LDMOS is verified by two-dimensional process simulator ATHENA and device simulator ATLAS[1]. The numerically calculated on-resistance($R_{ON}$) of the proposed LDMOS is $10.36\Omega-cm$ and breakdown voltage is 205V when $L_{dr}=7{\mu}m$ with step doped surface.

• 한국전기전자재료학회논문지
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• 제13권2호
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• pp.125-130
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• 2000

Two step growth of reduced pressure chemical vapor eposition has been successfully developed to achieve in-situ phosphorus-doped silicon epilayers, and the characteristic evolution on their microstructures has been investigated using scanning electron microscopy, transmission electron microscopy, and secondary ion mass spectroscopy. The two step growth, which employs heavily in-situ P doped silicon buffer layer grown at low temperature, proposes crucial advantages in manipulating crystal structures of in-situ phosphorus doped silicon. In particular, our experimental results showed that with annealing of the heavily P doped silicon buffer layers, high-quality epitaxial silicon layers grew on it. the heavily doped phosphorus in buffer layers introduces into native oxide and plays an important role in promoting the dispersion of native oxides. Furthermore, the phosphorus doping concentration remains uniform depth distribution in high quality single crystalline Si films obtained by the two step growth.

• Journal of Electrochemical Science and Technology
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• 제10권1호
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• pp.61-68
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• 2019

Well aligned $SnO_2$-doped ZnO nanorods were prepared by single step or 2-step electrochemical depositions in a mixture solution of zinc nitrate hexahydrate, ammonium hydroxide solution and 0.1 M tin chloride pentahydrate. The morphologies of electrochemically deposited $SnO_2$-doped ZnO were transformed from plain (or network) structures at low reduction potential to needles on hills at high reduction potential. Well aligned ZnO was prepared at intermediate potential ranges. Reduction reagent and a high concentration of Zn precursor were required to fabricate $SnO_2$ doped ZnO nanorods. When compared to results obtained by single step electrochemical deposition, 2-step electrochemical deposition produced a much higher density of nanorods, which was ascribed to less potential being required for nucleation of nanorods by the second-step electrochemical deposition because the surface was activated in the first-step. Mechanisms of $SnO_2$ doped ZnO nanorods prepared at single step or 2-step was described in terms of applied potential ranges and mass-/charge- limited transfer.

• 한국전기전자재료학회논문지
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• 제13권2호
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• pp.95-100
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• 2000

For the well-controlled growing in-situ heavily phosphorus doped polycrystalline Si films directly on Si wafer by reduced pressure chemical vapor deposition, a study is made of the two step growth. When in-situ heavily phosphorus doped Si films were deposited directly on Si (100) wafer, crystal structure in the film is not unique, that is, the single crystal to polycrystalline phase transition occurs at a certain thickness. However, the well-controlled polycrtstalline Si films deposited by two step growth grew directly on Si wafers. Moreover, the two step growth, which employs crystallization of grew directly on Si wafers. Moreover, the two step growth which employs crystallization of amorphous silicon layer grown at low temperature, reveals crucial advantages in manipulating polycrystal structures of in-situ phosphorous doped silicon.

• Journal of Electrochemical Science and Technology
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• 제10권3호
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• pp.271-275
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• 2019

Anodic $TiO_2$ nanotubes were simultaneously grown and doped with $RuO_2$ by single-step anodization in a negatively-charged $RuO_4{^-}$ precursor. Subsequently, a high positive voltage was imposed on the nanotubes in an $F^-$-based electrolyte (a process referred to as potential shock), which led to the formation of a through-hole $RuO_2$-doped $TiO_2$ nanotube membrane without significant loss of the $RuO_2$ catalyst. XPS results confirmed that the doped Ru metal was converted into $RuO_2$ as the potential shock voltage increased. Further increases in the potential shock voltage led to the formation of $RuO_x/Ru$ in the $TiO_2$ nanotubes. All of our results clearly showed that a through-hole catalyst-doped $TiO_2$ nanotube membrane can be produced by a sequence consisting of single-step anodization and the potential shock process.

• 한국재료학회지
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• 제22권4호
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• pp.207-210
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• 2012

The preparation of $Sm_2O_3$ doped $CeO_2$ in Igepal CO-520/cyclohexane reverse micelle solutions has been studied. In the present work, we synthesized nanosized $Sm_2O_3$ doped $CeO_2$ powders by reverse micelle process using aqueous ammonia as the precipitant; hydroxide precursor was obtained from nitrate solutions dispersed in the nanosized aqueous domains of a micro emulsion consisting of cyclohexane as the oil phase, and poly (xoyethylene) nonylphenylether (Igepal CO-520) as the non-ionic surfactant. The synthesized and calcined powders were characterized by Thermogravimetry-differential thermal analysis (TGA-DTA), X-ray diffraction analysis (XRD), and Transmission electron microscopy (TEM). The crystallite size was found to increase with increase in water to surfactant (R) molar ratio. Average particle size and distribution of the synthesized $Sm_2O_3$ doped $CeO_2$ were below 10 nm and narrow, respectively. TG-DTA analysis shows that phase of $Sm_2O_3$ doped $CeO_2$ nanoparticles changed from monoclinic to tetragonal at approximately $560^{\circ}C$. The phase of the synthesized $Sm_2O_3$ doped $CeO_2$ with heating to $600^{\circ}C$ for 30 min was tetragonal $CeO_2$. This study revealed that the particle formation process in reverse micelles is based on a two step model. The rapid first step is the complete reduction of the metal to the zero valence state. The second step is growth, via reagent exchanges between micelles through the inter-micellar exchange.

• 한국전기전자재료학회논문지
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• 제11권9호
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• pp.705-710
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• 1998

Intrinsic gettering is usually to improve wafer quality, which is an important factor for reliable ULSI devices. In order to generate oxygen precipitation in lightly and heavily boron doped silicon wafers with or without high $^75 As^+$ ion implantation, the 2-step annealing method was adopted. After annealing, the were cleaved and etched with th Wright etchant. The morphology of cross section on samples was inspected by FESEM(field emission scanning electron microscopy). The morphology of unimplanted samples was rater rough than that of the implanted. Oxygen precipitation density observed by an optical microscope in lightly boron doped samples was about 3$\times10^6/cm^3$. However, in heavily boron doped samples, the density of oxygen precipitation was largest at $600^{\circ}C$ in 1st annealing, and decreased abruptly until $800^{\circ}C$, But it increased slightly at $1000^{\circ}C$ and was independent with the implantation.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.40-44
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• 2011

Recent studies in crystalline silicon solar cell fabrication have been focused on high efficiency and low cost. However, the rising of the cost results in additional processes to approach high efficiency. The fabrication process also becomes complicated with additional technologies. In this paper, we studied the selective emitter formation with phosphorous paste to improve the conversion efficiency. Selective emitter formations like two-step diffusion or etch-back method require at least one more step compared in the conventional line since heavily and lightly doped area was needed to form separately.However,one-step diffusion process is the method diffusing heavily and lightly doped area at the same time only with additional screen-printing step. This study lays the foundation for the simple way to form the selective emitter.

• 한국재료학회지
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• 제19권5호
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• pp.259-264
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• 2009

In this study we investigated the effect of the multi-step texturing process on the electrical and optical properties of hydrogenated Al-doped zinc oxide (HAZO) thin films deposited by rf magnetron sputtering. AZO films on glass were prepared by changing the $H_2/(Ar+H_2)$ ratio at a low temperature of $150^{\circ}C$. The prepared HAZO films showed lower resistivity and higher carrier concentration and mobility than those of non-hydrogenated AZO films. After deposition, the surface of the HAZO films was multi-step textured in diluted HCl (0.5%) for the investigation of the change in the optical properties and the surface morphology due to etching. As a result, the HAZO film fabricated under the type III condition showed excellent optical properties with a haze value of 52.3%.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.93-96
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• 2000

In this study, we investigated the electromagnetic properties of Mn-Zn ferrite doped with rare earth oxide (Dy$_2$O$_3$, Er$_2$O$_3$). The main composition is 52mo1% $\alpha$-Fe$_2$O$_3$, 25mo1% Mn$_3$O$_4$23mo1% ZnO and doped with them(0.05wt%~0.25wt%, step:0.05wt%). An experimental process has advanced by conventional ferrimagnetism manufacturing that was prepared by standard ceramic techniques. The XRD pattern of all doped sample were observed spinel and secondary phase. The density of sample were measured nearly constant value. As increased the additive, resistivity, initial permeability and real component of the series complex permeability increased with setting limits each other. In case of Mn-Zn ferrite excess doped with them, resistivity, initial permeability and real component of the series complex permeability decreased and magnetic loss increased in proportion to increasing the additive.