• 한국전기전자재료학회논문지
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• 제22권6호
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• pp.462-465
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• 2009

Schottky barrier thin film transistors (SB-TFT) on polycrystalline silicon(poly-Si) are fabricated by platinum silicided source/drain for p-type SB-TFT. High quality poly-Si film were obtained by crystallizing the amorphous Si film with excimer laser annealing (ELA) or solid phase crystallization (SPC) method, The fabricated poly-Si SB-TFTs showed low leakage current level and a large on/off current ratio larger than 10), Significant improvement of electrical characteristics were obtained by the additional forming gas annealing in 2% $H_2/N_2$ ambient, which is attributed to the termination of dangling bond at the poly-Si grain boundaries as well as the reduction of interface trap states at gate oxide/poly-Si channel.

• Journal of Information Display
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• 제11권1호
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• pp.12-16
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• 2010

The effect of the crystallization and activated annealing of Si films using an excimer laser and the new CW blue laser are described and compared with furnace annealing for application in advanced TFTs and for future applications. Pulsed excimer laser annealing (ELA) is currently being used extensively as a low-temperature poly-silicon (LTPS) process on glass substrates as its efficiency is high in the ultra-violet (UV) region for thin Si films with thickness of 40-60 nm. ELA enables extremely low resistivity relating to high crystallinity for both the n- and p-type Si films. On the other hand, CW blue laser diode annealing (BLDA) enables the smooth Si surface to have arbitral crystal grains from micro-grains to an anisotropic huge grain structure only by controlling its power density. Both annealing techniques are expected to be applied in the future advanced TFT systems.

• 반도체디스플레이기술학회지
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• 제6권2호
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• pp.15-18
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• 2007

Effects of $O_2$ flow during deposition on Si crystallization at low substrate temperature were studied. Silicon thin films were prepared on $SiO_2$ substrates in a low-pressure chemical vapor deposition chamber using a mixture of $SiH_4$ and $H_2$. In some cases $O_2$ was intentionally introduced during deposition. Growth of poly silicon was observed at the substrate temperature as low as $480^{\circ}C$ when $O_2$ was flowed during deposition implying that crystallization of Si was enhanced by $O_2$ flow. On the other hand, $O_2$ flow did not show any significant effects at higher substrate temperature, where deposition rate is relatively fast. Enhancement mechanism of Si crystallization by $O_2$ flow was suggested from these results.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1407-1411
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• 2003

Due to the heat confinement in the shallow region of the target for a short time scale, pulsed laser annealing has received increasing interest for the fabrication of poly-Si thin film transistors(TFTs) on glass as a low cost substrate in the flat panel displays. The formation and growth mechanisms of poly silicon(poly-Si) grains in thin films are investigated using an excimer laser crystallization system. To understand the crystallization mechanism, the grain formations are observed by FESEM analysis. The optical reflectance and transmittance during the crystallization process are measured using HeNe laser optics. A two-step ELC(Excimer Laser Crystallization) process is applied to enhance the grain formation uniformity.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.656-660
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• 2003

We studied the crystallization behavior of LP-CVD a-Si film using UV pulsed laser. With increase in the shot number of irradiation by fixing its energy density, poly-Si film having a large grain size of $0.5 {\mu}m$ was obtained. By analyzing the crystallized Si films using optical analysis such as Raman spectroscopy or AFM technique etc., conspicuous correlation between the grain size and the resultant film properties such as the stress or the roughness has been found. With the increase in the energy density or the shots number of laser, remarkable grain growth occurred following to the roughness formation corresponding to the increase in the tensile stress.

• Current Photovoltaic Research
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• 제2권1호
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• pp.1-7
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• 2014

We developed a method of growing thin Si film at $600^{\circ}C$ by hot wire CVD using a very thin large-grained poly-Si seed layer for thin-film Si solar cells. The seed layer was prepared by crystallizing an amorphous Si film by vapor-induced crystallization using $AlCl_3$ vapor. The average grain size of the p-type epitaxial Si layer was about $20{\mu}m$ and crystallographic defects in the epitaxial layer were mainly low-angle grain boundaries and coincident-site lattice boundaries, which are special boundaries with less electrical activity. Moreover, with a decreasing in-situ boron doping time, the mis-orientation angle between grain boundaries and in-grain defects in epitaxial Si decreased. Due to fewer defects, the epitaxial Si film was high quality evidenced from Raman and TEM analysis. The highest mobility of $360cm^2/V{\cdot}s$ was achieved by decreasing the in-situ boron doping time. The performance of our preliminary thin-film solar cells with a single-side HIT structure and $CoSi_2$ back contact was poor. However, the result showed that the epitaxial Si film has considerable potential for improved performance with a reduced boron doping concentration.

• 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.

• 한국결정성장학회지
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• 제29권2호
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• pp.50-53
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• 2019

박막 태양전지에 주로 적용되는 다결정 규소층을 AIC(Aluminum Induced Crystallization) 공정을 이용하여 제조하였다. 결정립의 확대를 위하여 selective diffusion barrier 사용하였다. 이 diffusion barrier는 $Al_2O_3$ 막을 사용하였다. 공정시간의 단축을 위하여 열처리는 RTA(Rapid Thermal Annealing) 공정으로 진행하였다. 비정질 실리콘의 결정화는 XRD 측정을 통해 분석했다. 그 결과 $500^{\circ}C$에서 결정화되었으며, 결정 크기는 $15.9{\mu}m$로 계산되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.118-119
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• 2007

High performance three-dimensional (3-D) stacked poly-Si complementary metal-oxide semiconductor (CMOS) inverters with a high quality laser crystallized channel were fabricated. Low temperature crystallization methods of a-Si film using the excimer-laser annealing (ELA) and sequential lateral solidification (SLS) were performed. The NMOS thin-film-transistor (TFT) at lower layer of CMOS was fabricated on oxidized bulk Si substrate, and the PMOS TFT at upper layer of CMOS was fabricated on interlayer dielectric film. The 3-D stacked poly-Si CMOS inverter showed excellent electrical characteristics and was enough for the vertical integrated CMOS applications.