• 한국세라믹학회지
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• 제28권11호
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• pp.859-864
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• 1991

High quality lead titanate thin films were fabricated by spin coating on a silicon substrate. The resulting dried gel layers were uniform in thickness through 2$\times$2 $\textrm{cm}^2$ area, and polycrystalline perovskite structures developed almost crack free with a heat treatment above 50$0^{\circ}C$ in films with thickness above 360 nm. Metastable pyrochlore structures were observed in films with thickness of 160 nm when heat treated at 500 and $600^{\circ}C$, but these structure did not appear in films with thickness of 360 nm. The thickness dependence in crystal structure of films was studied. by varying the substrate condition and analyzing the interface between the film and substrate. In native oxide films on silicon stbstrates, amorphous dried gel layers were heterogeneously nucleated. Metastable cubic pyrochlore structure could be crystallized in amorphous native oxide.

• Journal of Information Display
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• 제10권3호
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• pp.117-120
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• 2009

A new crystallization method for amorphous silicon, called selective area heating (SAH), was proposed. The purpose of SAH is to improve the reliability of amorphous silicon films with extremely low thermal budgets to the glass substrate. The crystallization time shortened from that of the conventional solid-phase crystallization method. An isolated thin heater for SAH was fabricated on a quartz substrate with a Pt layer. To investigate the crystalline properties, Raman scattering spectra were used. The crystalline transverse optic phonon peak was at about 519 $cm^{-1}$, which shows that the films were crystallized. The effect of the crystallization time on the varying thickness of the $SiO_2$ films was investigated. The crystallization area in the 400nm-thick $SiO_2$ film was larger than those of the $SiO_2$ films with other thicknesses after SAH at 16 W for 2 min. The results show that a $SiO_2$ capping layer acts as storage layer for thermal energy. SAH is thus suggested as a new crystallization method for large-area electronic device applications.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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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

• Journal of the Optical Society of Korea
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• 제5권1호
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• pp.1-4
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• 2001

The results of investigating $SiL_{2,3}$/ X-ray emission valence spectra of amorphous silicon films irradiated by excimer laser are presented. It is found that laser annealing leads to crystallization of amorphous silicon films and the crystallinity increases with the laser energy density from 250 to 400 mJ/$\textrm{cm}^2$. The vertical structure of the film is investigated by changing the accelerating voltage on the X-ray tube, and the chemical and structural state of Si$_3$N$_4$ buffer layer is found not to be changed by the excimer laser treatment.

• 반도체디스플레이기술학회지
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• 제16권2호
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• pp.39-43
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• 2017

It was confirmed that the silicon thin films fabricated on the p-Si (100) substrates by using DIPAS (DiIsoPropylAminoSilane) and TDMA-Sb (Tris-DiMethylAminoAntimony) sources by RPCVD method were amorphous and n-type silicon. The fabricated amorphous n-type silicon films had electron carrier concentrations and electron mobilities ranged from $6.83{\times}10^{18}cm^{-3}$ to $1.27{\times}10^{19}cm^{-3}$ and from 62 to $89cm^2/V{\cdot}s$, respectively. The ideality factor of the pn junction diode fabricated on the p-Si (100) substrate was about 1.19 and the efficiency of the fabricated pn solar cell was 10.87%.

• 한국진공학회지
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• 제11권4호
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• pp.225-229
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• 2002

LPCVD로 $560^{\circ}C$와 $650^{\circ}C$ 온도에서 실리콘 박막을 제작하였다. 온도에 따른 천이온도를 살펴보았으며, 비정질로 제작된 실리콘 박막을 $900^{\circ}C$와 $1100^{\circ}C$에서 열처리하였다. 제작된 박막에 대해서 XRD, SEM, ellipsometer, $Tektak^3$, Tencer FLX-2320등 그 외 장비를 사용하여, 박막의 결정 방향, 표면 거칠기, 활성화 에너지, 잔류 응력 등을 조사하였다. 본 실험을 통해 $560^{\circ}C$에서 비정질로 증착시키고 $900^{\circ}C$ -$1100^{\circ}C$ 열처리 통해 얻은 다결정실리콘 박막은 처음부터 다결정으로 제작한 박막에 비해 낮은 잔류 응력과 표면 거칠기를 보였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.141-141
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• 2010

The effect of thermal anneal on the characteristics of structural properties and the enhancement of luminescence and photovoltaic (PV) characteristics of silicon-rich silicon-nitride films were investigated. By using an ultra high vacuum ion beam sputtering deposition, B-doped silicon-rich silicon-nitride (SRSN) thin films, with excess silicon content of 15 at. %, on P-doped (n-type) Si substrate was fabricated, sputtering a highly B doped Si wafer with a BN chip by N plasma. In order to examine the influence of thermal anneal, films were then annealed at different temperature up to $1100^{\circ}C$ under $N_2$ environment. Raman, X-ray diffraction, and X-ray photoemission spectroscopy did not show any reliable evidence of amorphous or crystalline Si clusters allowing us concluding that nearly no Si nano-cluster could be formed through the precipitation of excess Si from SRSN matrix during thermal anneal. Instead, results of Fourier transform infrared and X-ray photoemission spectroscopy clearly indicated that defective, amorphous Si-N matrix of films was changed to be well-ordered thanks to high temperature anneal. The measurement of spectral ellipsometry in UV-visible range was carried out and we found that the optical absorption edge of film was shifted to higher energy as the anneal temperature increased as the results of thermal anneal induced formation of $Si_3N_4$-like matrix. These are consistent with the observation that higher visible photoluminescence, which is likely due to the presence of Si-N bonds, from anneals at higher temperature. Based on these films, PV cells were fabricated by the formation of front/back metal electrodes. For all cells, typical I-V characteristic of p-n diode junction was observed. We also tried to measure PV properties using a solar-simulator and confirmed successful operation of PV devices. Carrier transport mechanism depending on anneal temperature and the implication of PV cells based on SRSN films were also discussed.

• 대한전자공학회논문지
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• 제25권5호
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• pp.501-508
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• 1988

This paper presents the light-induced effects on the elelctrical and optical properties of undoped and doped hydrogenated amorphous silicon films. The changes in the conductivities and the activation energies of various types of a-Si:H films due to the prolonged exposure to light have been characterized as a function of deposition conditions and illumination periods. The dark conductivity changes may be quenched for heavier doped a-Si:H films. We have also analyzed the variations of micro-structure of a-Si:H film such as silicon-hydrogen bondings in the rocking and stretching modes utilizing infrared spectroscopy. From the experimental results, it is elucidated that doping effects must be crucial to the degradations of the fundamental properties of a-Si:H due to light-induced effects.

• 한국표면공학회지
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• 제34권5호
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• pp.503-509
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• 2001

Thin films of hydrogenated amorphous silicon (a-Si : H) and hydrogenated amorphous silicon carbide (a-SiC:H) of different compositions were deposited on Si(100) wafer and glass by RF plasma-enhanced chemical vapor deposition (RF-PECVD). In the present work, we have investigated the effects of the RF power on the properties, such as optical band gap, transmittance and crystallinity. The Raman data show that the a-Si:H material consists of an amorphous and crystalline phase for the co-presence of two peaks centered at 480 and $520 cm^{-1}$ . The UV-VIS data suggested that the optical energy band gap ($E_{g}$ ) is not changed effectively with RF power and the obtained $E_{g}$(1.80eV) of the $\mu$c-Si:H thin film has almost the same value of a-Si:H thin film (1.75eV), indicating that the crystallity of hydrogenated amorphous silicon thin film can mainly not affected to their optical properties. However, the experimental results have shown that$ E_{g}$ of the a-SiC:H thin films changed little on the annealing temperature while $E_{g}$ increased with the RF power. The Raman spectrum of the a-SiC:H thin films annealed at high temperatures showed that graphitization of carbon clusters and microcrystalline silicon occurs.

• 한국재료학회지
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• 제5권2호
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• pp.203-207
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• 1995

Polysilicon this film transistors (poly-Si TFTs) with different channel dimensions were fabricated on low-temperature crystalized amorphous silicon films and on as-deposited polysilicon films. The electrical characteristics of these TFTs were characterized and compared. The performance of the TFTs fabricated on the solid-phase crystalized amophous silicon films ws showon to be superior to that of the TFTs fabricated on the as-deposited polysilicon films. It was found that the performance of poly-Si TFTs depends strongly on the material characteristics of the polysilicon films used as the active layers, but only weakly on the channel dimensions.