• Journal of the Microelectronics and Packaging Society
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• v.9 no.2
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• pp.49-54
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• 2002

Cobalt silcides thin films were prepared on Poly-Si/$SiO_2$/Si substrates by Co metal depostion using E-beam evaporation method and rapid thermal annealing for the application of inkjet printing heater. The crystal phases and composition distributions of the films were investigated as functions of the rapid thermal annealing (RTA) temperatures (600~$900^{\circ}C$) and times (20~40 sec). The high temparature thermal stability was also investigated by the analysis of sheet resistance and crystalline properties. The stable $CoSi_2$ phases were obtained by the RTA annealing at $800^{\circ}C$ for 20 seconds showing $0.8 \Omega /\Box$ of sheet resitance. However, the sheet resistances were sharply increased at below $700^{\circ}C$ due to changes of crystalline phases. The temperature resistance coefficient of heating elements was found to be about $0.0014/^{\circ}C$, and the obtained cobalt silicided films can be applied to the printer heating elements.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.795-800
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• 2008

A sublimation method using the SiC seed crystal and SiC powder as the source material is commonly adopted to grow SiC bulk single crystal. However, it has proved to be difficult to achieve the high quality crystal and the process reliability because SiC single crystal should be grown at very high temperature in closed system. The present research was focused to improve SiC crystal quality grown by PVT method through using the new inner guide tube. The new inner guide tube was designed to prevent the enlargement of polycrystalline region into single crystalline region and to enlarge the diameter of SiC single crystal. The 6H-SiC crystals were grown by conventional PVT process. The seed adhered on seed holder and the high purity SiC source materials are placed on opposite side in sealed graphite crucible surrounded by graphite insulation. The SiC bulk growth was conducted around 2300 $^{\circ}C$ of growth temperature and 50 mbar in an argon atmosphere of growth pressure. The axial thermal gradient across the SiC crystal during the growth was estimated in the range of 15${\sim}$20 $^{\circ}C$/cm.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1238_1239
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• 2009

본 논문에서는 ELA poly-Si TFT보다 뛰어난 균일도를 갖고, a-Si:H TFT보다 전기적 안정도가 우수한 PMOS SPC-Si TFT의 특성을 연구하였다. SPC-Si의 계면 특성을 향상 시키기 위해 $SiO_2$ 게이트 절연막을 증착하기 전에 Solid Phase Crystalline 실리콘(SPC-Si) 채널 영역에 다양한 H2 플라즈마 처리를 해주었다. PECVD를 이용하여 100W에서 H2 플라즈마 처리를 5분 해주었을 때 SPC-Si TFT의 전기적 특성이 향상되는 것을 볼 수 있는데, $V_{TH}$가 약 -3.91V, field effect mobility가 $22.68cm^2$/Vs, 그리고 Subthreshold swing이 0.64 정도를 보였다. 또한 소자에 Hot carrier stress($V_{GS}$=14.91V, $V_{DS}$=-15V, for 2,000sec)를 주었을 때도 전기적 특성이 변하지 않았으며, 일정한 bias stress($V_{GS}$=-15V, $V_{DS}$=-10V, for 2,000sec)를 가하였을 때도 $V_{TH}$가 증가하지 않았다. 이러한 결과를 통해 SPC-Si가 poly-Si TFT보다 더욱 안정함을 알 수 있었다.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1427-1429
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• 2001

Polycrystalline silicon(poly-Si) films are deposited on low temperature glass substrate by Hot-Wire CVD(HWCVD). The structural properties of the poly-Si films are strongly dependent on the wire temperature($T_w$). The films deposited at high $T_w$ of 2000$^{\circ}C$ have superior crystalline properties; average lateral grain sizes are larger than $1{\mu}m$ and there at·e no vertical grain boundaries. The surface of the high $T_w$ samples are naturally textured like pyramid shape. These large grain size and textured surface are believed to give high current density when applied to solar cells. However, the poly-si films are structurally porous and contains high defect density, by which high concentration of C and O resulted within the films by air-penetration after removed from chamber.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.957-961
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• 2004

In order to realize high performance thin film transistor (TFT) on plastic substrate, Si film was deposited on plastic substrate at 170$^{\circ}C$ by using inductivity coupled plasma chemical vapor deposition (ICPCVD). Hydrogen concentration in as-deposited Si film was 3.8% which is much lower than that in film prepared by using conventional plasma enhanced chemical vapor deposition (PECVD). Si film was deposited as micro crystalline phase rather than amorphous phase even at 170$^{\circ}C$ because of high density plasma. By step-by-step Excimer laser annealing, dehydrogenation and recrystallization of Si film were carried out simultaneously. With step-by-step annealing and optimization of underlayer structure, it has succeeded to achieve large grain size of 300nm by using ICPCVD. Base on these results, poly-Si TFT was fabricated on plastic substrate successfully, and it is sufficient to drive pixels of OLEDs, as well as LCDs.

• Proceedings of the Korean Magnestics Society Conference
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• 2004.06a
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• pp.86-87
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• 2004

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.153-153
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• 2011

유리나 폴리머를 기판으로 하는 TFT(Thin film transistor), solar cell에서는 낮은 공정 온도에서($200{\sim}500^{\circ}C$) amorphous semiconductor thin film을 poly-crystal semiconductor thin film으로 결정화 시키는 기술이 매우 중요하게 대두 되고 있다. Ge은 Si에 비해 높은 carrier mobility와 낮은 녹는점을 가지므로, 비 저항이 낮을 뿐만 아니라 더 낮은 온도에서 결정화 할 수 있다. 하지만 일반적으로 쓰이는 Ge의 결정화 방법은 비교적 높은 열처리 온도를 필요로 하거나, 결정화된 원소에 남아있는 metal이 불순물 역할을 한다는 문제점, 그리고 불균일한 결정크기를 만든다는 단점이 있었다. 그 중에서도 현재 가장 많이 쓰이고 있는 MIC, MILC는 metal과 a-Ge이 접촉되는 interface나, grain boundary diffusion에 의해 핵 생성이 일어나고, 결정이 성장하는 메커니즘을 가지고 있으므로 단순 증착과 열처리 만으로는 앞서 말한 단점을 극복하는데 한계를 가지고 있다. 이에 PIII&D 장비를 이용하면, 이온 주입된 원소들이 모재와 반응 할 수 있는 표면적이 커짐으로 핵 생성을 조절 할 수 있을 뿐만 아니라, 이온 주입 시 발생하는 self annealing effect로 결정 크기까지도 조절할 수 있다. 또한 이러한 모든 process가 한 진공 장비 내에서 이루어지므로 장비의 단순화와, 공정간 단계별로 발생하는 불순물과 표면산화를 막을 수 있으므로 절연체 위에 저항이 낮고, hall mobility가 높은 poly-crystalline Ge thin film을 만들 수 있다. 본 연구에서는, 주로 핵 생성과정에서 seed를 만드는 이온주입 조건과, 결정 성장이 일어나는 증착 조건에 따라서 Ge의 결정방향과 크기가 많은 차이를 보이는데, 이는 HR-XRD(High resolution X-ray Diffractometer)와 Raman spectroscopy를 이용하여 측정 하였으며, SEM과 AFM으로 결정의 크기와 표면 거칠기를 측정하였다. 또한 Hall effect measurement를 통해 poly-crystalline thin film 의 저항과 hall mobility를 측정하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.408-409
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• 2006

The polycrystalline 3C-SiC thin films heteroepitaxially grown by LPCVD method using single precursor 1. 3-disilabutane at $850^{\circ}C$. The crystallinity of the 3C-SiC thin film. was analyzed by XPS. Residual strain was investigated by Raman scattering. The surface morphology and voids between SiC and $SiO_2$ were measured by SEM. The grown poly 3C-SiC thin film is very good crystalline quality, surface like mirror, and low defect and strain. Therefore, the polycrystalline 3C-SiC is suitable for harsh environment MEMS applications.

• Journal of Sensor Science and Technology
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• v.20 no.3
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• pp.168-171
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• 2011

Porous 3C-SiC(pSiC) samples with different pore diameters were prepared from poly crystalline N-type 3C-SiC by electrochemical anodization. The pSiC surface was chemically modified by the sputtering of Pd and Pt nano-particles as a hydrogen catalyst. Changes in resistance were monitored with hydrogen concentrations in the range of 110 ppm - 410 ppm. The variations of the electrical resistance in the presence of hydrogen demonstrated that Pd and Pt-deposited pSiC samples have the ability to detect hydrogen at room temperature. Regardless of the catalyst, the 25 nm pore diameter samples showed good response and recovery properties. However, the 60 nm samples showed unstable and slow response. It was found that the pore size affects the catalyst reaction and consequently, results in changes of the sensitivity to hydrogen.