• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.456-456
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• 2009

Boron doping on an n-type Si wafer is requisite process for IBC (Interdigitated Back Contact) solar cells. Fiber laser annealing is one of boron doping methods. For the boron doping, uniformly coated or deposited film is highly required. Plasma enhanced chemical vapor deposition (PECVD) method provides a uniform dopant film or layer which can facilitate doping. Because amorphous silicon layer absorption range for the wavelength of fiber laser does not match well for the direct annealing. In this study, to enhance thermal affection on the existing p-a-Si:H layer, a ${\mu}c$-Si:H intrinsic layer was deposited on the p-a-Si:H layer additionally by PECVD. To improve heat transfer rate to the amorphous silicon layer, and as heating both sides and protecting boron eliminating from the amorphous silicon layer. For p-a-Si:H layer with the ratio of $SiH_4$ : $B_2H_6$ : $H_2$ = 30 : 30 : 120, at $200^{\circ}C$, 50 W, 0.2 Torr for 30 minutes, and for ${\mu}c$-Si:H intrinsic layer, $SiH_4$ : $H_2$ = 10 : 300, at $200^{\circ}C$, 30 W, 0.5 Torr for 60 minutes, 2 cm $\times$ 2 cm size wafers were used. In consequence of comparing the results of lifetime measurement and sheet resistance relation, the laser condition set of 20 ~ 27 % of power, 150 ~ 160 kHz, 20 ~ 50 mm/s of marking speed, and $10\;{\sim}\;50 {\mu}m$ spacing with continuous wave mode of scanner lens showed the correlation between lifetime and sheet resistance as $100\;{\Omega}/sq$ and $11.8\;{\mu}s$ vs. $17\;{\Omega}/sq$ and $8.2\;{\mu}s$. Comparing to the singly deposited p-a-Si:H layer case, the additional ${\mu}c$-Si:H layer for doping resulted in no trade-offs, but showed slight improvement of both lifetime and sheet resistance, however sheet resistance might be confined by the additional intrinsic layer. This might come from the ineffective crystallization of amorphous silicon layer. For the additional layer case, lifetime and sheet resistance were measured as $84.8\;{\Omega}/sq$ and $11.09\;{\mu}s$ vs. $79.8\;{\Omega}/sq$ and $11.93\;{\mu}s$. The co-existence of $n^+$layeronthesamesurfaceandeliminating the laser damage should be taken into account for an IBC solar cell structure. Heavily doped uniform boron layer by fiber laser brings not only basic and essential conditions for the beginning step of IBC solar cell fabrication processes, but also the controllable doping concentration and depth that can be established according to the deposition conditions of layers.

• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.483-489
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• 2007

Polyaniline (PANI)/Polyimide (PI) membranes were prepared and the effects of PANI contents and doping on the structural properties and gas separation properties were studied. The polyamic acid (PAA) solution was prepared by the polycondensation reaction of 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 4,4'-oxydianiline (ODA) in 1-methyl-2-pyrrolydinone (NMP) solvent. The PANI/PI blends were obtained by mixing PAA solution and PANI solution, and were doped with 1 M aqueous HCl solution for 24 h. The structural characterizations of the as-cast and doped membranes were examined by FT-IR, XRD, and TGA. The gas permeation experiments with $H_2$, $CO_2$, $O_2$, $N_2$, and $CH_4$ were carried out by variable pressure method at $30^{\circ}C$ and 5 atm. For all gases tested, the permeability coefficients of the blends decreased with increasing PANI content and the magnitude of permeability was in the order of $H_2$ > $CO_2$ > $O_2$ > $N_2$ > $CH_4$. The permeability for PANI/PI membranes decreased after the doping process while the permselectivity increased. For $H_2/CH_4$ separation, the doped PANI/PI (75/25) membrane has a permselectivity of 991.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.31 no.2
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• pp.73-77
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• 2021

Ga-doped ZnO thin films by RF magnetron sputtering process were synthesized according to the deposition conditions of O2 and Ar atmosphere gases, and rapid heat treatment (RTA) was performed at 600℃ in an N2 atmosphere. The thickness of the deposited ZnO : Ga thin film was measured, the crystal phase was investigated by XRD pattern analysis, and the microstructure of the thin film was observed by FE-SEM and AFM images. The intensity of the (002) plane of the X-ray diffraction pattern showed a significant difference depending on the deposition conditions of the thin films formed by O2 and Ar atmosphere gas types. In the case of a single thin f ilm doped with Ga under O2 conditions, a strong diffraction peak was observed. Under O2 and Ar conditions, in the case of a multilayer thin film with Ga doping, only a peak on the (002) plane with a somewhat weak intensity was shown. In the FE-SEM image, it was observed that the grain size of the surface of the thin film slightly increased as the thickness increased. In the case of a multilayer thin film with Ga doping under O2 and Ar atmosphere conditions, the specific resistance was 6.4 × 10-4 Ω·cm. In the case of a single thin film with Ga doping under O2 atmosphere conditions, the resistance of the thin film decreased. The resistance decreased as the thickness of the Ga-doped ZnO thin film increased to 2 ㎛, showing relatively a low specific resistance of 1.0 × 10-3 Ω·cm.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.434-434
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• 2012

Despite recent efforts for fabricating flexible transparent conducting films (TCFs) with low resistance and high transmittance, several obstacles to meet the requirement of flexible displays still remain. Indium tin oxide (ITO) thin films, which have been traditionally used as the TCFs, have a serious obstacle in TCFs applications. SWNTs are the most appropriate materials for conductive films for displays due to their excellent high mechanical strength and electrical conductivity. Recently, it has been demonstrated that acid treatment is an efficient method for surfactant removal. However, the treatment has been reported to destroy most SWNT. In this work, the fabrication by the spraying process of transparent SWNT films and reduction of its sheet resistance by Au-ionic doping treatment on PET substrates is researched. Arc-discharge SWNTs were dispersed in deionized water by adding sodium dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWNT was spray-coated on PET substrate and dried on a hotplate. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then was doped with Au-ionic doping treatment, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. This was confirmed and discussed on the XPS and UPS studies. We show that 87 ${\Omega}/{\Box}$ sheet resistances with 81% transmittance at the wavelength of 550 nm. The changes in electrical and optical conductivity of SWNT film before and after Au-ionic doping treatments were discussed. The effects of hole transport interface layer using Au-ionic doping SWNT on the performance of organic solar cells were investigated.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.5
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• pp.285-290
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• 2015

The phase change memory material is an active element in phase change memory and exhibits reversible phase transition behavior by thermal energy input. The doping of the phase change memory material with Ga leads to the increase of its crystallization temperature and the improvement of its amorphous stability. In this study, we investigated the effect of GaGe sputtering power on the formation of the phase change memory material including Ga. The deposition rate linearly increased to a maximum of 127 nm and the surface roughness remained uniform as the GaGe sputtering power increased in the range from 0 to 75 W. The Ga concentration in the thin film material abruptly increased at the critical sputtering power of 60 W. This influence of GaGe sputtering power was confirmed to result from a combined sputtering-evaporation process of Ga occurring due to the low melting point of Ga ($29.77^{\circ}C$).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.335-336
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• 2009

저가격 고효율 실리콘 태양전지를 구현하기 위하여 핵심적으로 적용되는 공정인 SOD(Spin on Doping) 확산공정 최적화에 관하여 연구하였다. n-type 도핑 물질로는 인(P509)을 사용하였으며, Spinning 속도와 Spinning 시간을 각 3000 rpm, 30 초로 고정하고 급속 열처리로에서 확산 온도와 확산 시간을 $800\;^{\circ}C\;{\sim}\;950\;^{\circ}C$, 2 분에서 20 분까지 가변하며 확산공정을 실시하였다. 4-Point Probe 장비로 에미터 표면 저항을 측정한 결과 확산 온도 $850\;^{\circ}C$에서 5분간 열처리 하여 확산 공정을 하였을 때 저가의 고효율 실리콘 태양전지를 구현하는데 적용 하기위한 $30\;{\sim}\;50\;{\Omega}$-sq의 에미터 표면 저항을 만족 시키는 $36\;{\Omega}$-sq의 값을 얻을 수 있었다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1430-1431
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• 2011

To develope the transparent conducting oxide(TCO) films is one of the essential technologies to improve various properties of electro-optical devices such as dye-sensitized solar cells(DSCs). ITiO thin film is considered one of the candidates as TCO electrodes of DSCs because it shows many advantages such as the high transparency in long wavelength range above 700nm and excellent properties of electrical necking between nanoporous TiO2 and ITiO transparent electrode. This paper presents the effect of sputtering processes on the structural, electrical and optical properties of ITiO thin film deposited by r.f. magnetron sputtering. The effect of doping concentration of Ti on the chemical compounds and C axis-orientation properties of were mainly studied experimentally. The morphology and electrical properties were greatly influenced by deposition processes, especially by the doping concentration of Ti. The $3.8{\times}10^{-4}{\Omega}{\cdot}cm$ of minimum volume resistivity were obtained under the experimental conditions of gas pressure 7mTorr, substrate temperature $300^{\circ}C$, and 2.5% of Ti doping concentration.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1706-1707
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• 2007

A possibility of work function engineering on ZnO thin film is studied by in-situ and ex-situ doping process. The work function of ZnO thin film decreases with increasing boron and phosphorus doping quantity. But, the work function of Al-doped ZnO (AZO) thin film increases as the boron doping quantity incresess. The range of work function change on ZnO thin films is 3.5 eV to 5.5 eV. This result shows that the work function of ZnO thin film is indeed engineerable by changing materials of dopants and their compositional distribution of surface. We also discuss the possible mechanism of work function engineering on ZnO thin films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1301-1307
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• 2004

Reduced pressure chemical vapor deposition(RPCYD) technology has been investigated for the growth of SiGe epitaxial films with two dimensional in-situ doped boron impurities. The two dimensional $\delta$-doped impurities can supply high mobility carriers into the channel of SiGe heterostructure MOSFETs(HMOS). Process parameters including substrate temperature, flow rate of dopant gas, and structure of epitaxial layers presented significant influence on the shape of two dimensional dopant distribution. Weak bonds of germanium hydrides could promote high incorporation efficiency of boron atoms on film surface. Meanwhile the negligible diffusion coefficient in SiGe prohibits the dispersion of boron atoms: that is, very sharp, well defined two-dimensional doping could be obtained within a few atomic layers. Peak concentration and full-width-at-half-maximum of boron profiles in SiGe could be achieved in the range of 10$^{18}$ -10$^{20}$ cm$^{-3}$ and below 5 nm, respectively. These experimental results suggest that the present method is particularly suitable for HMOS devices requiring a high-precision channel for superior performance in terms of operation speed and noise levels to the present conventional CMOS technology.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.93-97
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• 2011

In this paper, we discuss design considerations for an n-channel metal-oxide-semiconductor field-effect transistor (MOSFET) with a lateral asymmetric channel (LAC) doping profile. We employed a 0.35 ${\mu}M$ standard complementary MOSFET process for fabrication of the devices. The gates to the LAC doping overlap lengths were 0.5, 1.0, and 1.5 ${\mu}M$. The drain current ($I_{ON}$), transconductance ($g_m$), substrate current ($I_{SUB}$), drain to source leakage current ($I_{OFF}$), and channel-hot-electron (CHE) reliability characteristics were taken into account for optimum device design. The LAC devices with shorter overlap lengths demonstrated improved $I_{ON}$ and $g_m$ characteristics. On the other hand, the LAC devices with longer overlap lengths demonstrated improved CHE degradation and $I_{OFF}$ characteristics.