• 한국표면공학회지
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• 제25권6호
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• pp.287-292
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• 1992

Silicon nitride thin film (SiNx) was deposited onto the 3inch silicon wafer using an electron cyclotron resonance (ECR) plasma apparatus. The thin films which were deposited by changing the SiH4N2 gas flow rate ratio at 1.5mTorr without substrate heating were analyzed through the x-ray photo spectroscopy (XPS) and ellipsometer measurements, etc. Silicon nitride thin films prepared by the electron cyclotron resonance plasma chemical vapor deposition method at low substrate temperature (<10$0^{\circ}C$) exhibited excellent physical and electrical properties. The very uniform and good quality silicon nitride thin films were obtained. The characteristics of electron cyclotron resonance plasma were inferred from the analyzed results of the deposited films.

• 한국표면공학회지
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• 제23권4호
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• pp.218-224
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• 1990

Silicon nitride thin(SiNx) is deposited onto 3 inch silicon wafor using ECR plasma apparatus. For the two different plasma extraction windows size, the thin films which were deposited by changing the SiH4/N2 gas fole at at 1.5mTorr without substrate heating are analyzed through the XPS and wlliposometer measurements. The very uniform and good quality silicon nitride thin film were obtained with the analyzed results of the deposited films, and particularly, ion temperature perpendicular to the magnetic filed was nearly same as the neutral gas temperature. The large amount of plasma loss in the transport process following magnetic field lines could be seen from the plasma emission intensity measurements.

• 한국재료학회지
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• 제28권4호
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• pp.247-253
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• 2018

We examined the characteristics of indium tin zinc oxide (ITZO) thin film transistors (TFTs) on polyimide (PI) substrates for next-generation flexible display application. In this study, the ITZO TFT was fabricated and analyzed with a SiOx/SiNx gate insulator deposited using plasma enhanced chemical vapor deposition (PECVD) below $350^{\circ}C$. X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS) results revealed that the oxygen vacancies and impurities such as H, OH and $H_2O$ increased at ITZO/gate insulator interface. Our study suggests that the hydrogen related impurities existing in the PI and gate insulator were diffused into the channel during the fabrication process. We demonstrate that these impurities and oxygen vacancies in the ITZO channel/gate insulator may cause degradation of the electrical characteristics and bias stability. Therefore, in order to realize high performance oxide TFTs for flexible displays, it is necessary to develop a buffer layer (e.g., $Al_2O_3$) that can sufficiently prevent the diffusion of impurities into the channel.

• 한국진공학회지
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• 제21권1호
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• pp.29-35
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• 2012

수소화된 실리콘 질화막은 결정질 태양전지 산업에서 반사방지막과 패시베이션 층으로 널리 사용되고 있다. 또한, 수소화된 질화막은 금속 소성공정과 같은 높은 공정온도를 거친 후에도 결정질 실리콘 태양전지의 표면층으로서 충족되는 특성들이 변하지 않고 유지 되어야 한다. 본 연구에서는 Plasma enhanced chemical vapor deposition 장치를 이용한 수소화된 실리콘 질화막의 특성 변화에 대한 경향성을 알아보기 위하여 증착조건의 변수(온도, 증착거리, 무선주파수 전력, 가스비율 등)들을 다양하게 가변하여 증착조건의 최적화를 찾았다. 이후 수소화된 실리콘 질화막의 전구체가 되는 사일렌($SiH_4$)과 암모니아 ($NH_3$) 가스비를 변화시켜가며 결정질 실리콘 태양전지에 사용되기 위한 박막의 광학 전기 화학적 그리고 표면 패시베이션 특성들을 분석하였다. 가스 비율에 따른 수소화된 실리콘 질화막의 굴절율 범위는 1.90~2.20까지 나타내었다. 결정질 실리콘 태양전지에 사용하기 위한 가장 적합한 특성은 3.6 ($NH_3/SiH_4$)의 가스비율을 나타내었다. 이를 통하여 $156{\times}156mm$ 대면적 결정질 실리콘 태양전지를 제작하여 17.2 %의 변환 효율을 나타내었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.429-429
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• 2007

For various applications of liquid crystal displays (LCDs), the uniform alignment of liquid crystal (LC) molecules on treated surfaces is significantly important. Generally, a rubbing method has been widely used to align the LC molecules on polyimide (PI) surfaces. Rubbed PI surfaces have suitable characteristics, such as uniform alignment. However, the rubbing method has some drawbacks, such as the generation of electrostatic charges and the creation of contaminating particles. Thus, we strongly recommend a non contact alignment technique for future generations of large high-resolution LCDs. Most recently, the LC aligning capabilities achieved by ultraviolet and ion-beam exposures which are non contact methods, on diamond-like carbon (DLC) inorganic thin film layers have been successfully studied because DLC thin films have a high mechanical hardness, a high electrical resistivity, optical transparency, and chemical inertness. In addition, nitrogen-doped DLC (NDLC) thin films exhibit properties similar to those of the DLC thin films and a higher thermal stability than the DLC thin films because C:N bonding in the NDLC thin filmsis stronger against thermal stress than C:H bonding in the DLC thin films. Our research group has already studied the NDLC thin films by an ion-beam alignment method. The $SiN_x$ thin films deposited by plasma-enhanced chemical vapor deposition are widely used as an insulation layer for a thin film transistor, which has characteristics similar to those of DLC inorganic thin films. Therefore, in this paper, we report on LC alignment effects and pretilt angle generation on a $SiN_x$, thin film treated by ion-beam irradiation for various N ratios

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.56.1-56.1
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• 2010

결정질 실리콘 태양전지의 표면 ARC(Anti-reflection Coating)layer는 반사도를 줄여 광 흡수율을 증가시키고, passivation 효과를 통하여 표면 재결합을 감소 시켜 태양전지의 효율을 높이는 중요한 역할을 한다. Silicon nitride 박막은 외부 stress 요인에 대해 안정성을 담보할 수 있어야한다. 따라서, 본 연구에서는 굴절률 가변에 따른 silicon nitride 박막을 PECVD를 이용하여 증착하고, 항온/항습 stability test를 통해 박막의 안정성을 확인하였다. Silicon nitride 증착을 위해 PECVD를 이용하였고, 공정압력 0.8Torr, 증착온도 $450^{\circ}C$, 증착파워 300W에서 실험을 진행하였다 박막의 굴절률은 1.9~2.3의 범위로 가변하였다. 항온/항습에 대한 신뢰성을 test 하기 위하여 5시간동안의 test를 1cycle로 하여 20회 동안 실험을 실시하였다. 증착된 silicon nitride 박막의 lifetime은 firing 이후 57.8us로 가장 높았으며, 항온/항습 test 이후에도 유사한 경향을 확인 할 수 있었다. 또한, 100h 동안의 항온/항습 test 결과 silicon nitride 박막의 lifetme 감소는 8.5%에 불과했다. 본 연구를 통하여 온도와 습도의 변화에 따른 결정질 실리콘 태양전지의 SiNx 박막의 증착 공정 조건에 대한 신뢰성을 확인 할 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제29권5호
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• pp.392-399
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• 2008

Thin-film transistor (TFT) arrays for an x-ray detector require quite different design concept from that of the conventional active-matrix liquid crystal devices (AM-LCDs). In this paper anew design of TFT array which uses only SiNx for passivation layer is described to meet the detector performance and the product availability simultaneously. For the purpose of optimizing the design parameters of the TFT array, a Spice simulation was performed. As a result, some parameters, such as the TFT width, the data line capacitance, and the storage capacitance, were able to be fixed. The other parameters were decided within a permissible range of the TFT process especially the photolithography process and the wet etch process. Then we adapted the TFT array which had been produced by the proposed design to our prototype model (FDXD-1417 and evaluated it clinically by comparing with a commercial model (EPEX, Hologic, Beford, USA). The results say that our prototype model is slightly better than EPEX system in chest PA images. So we can prove the technical usefulness and the commercial values of the proposed TFT design.

• 한국재료학회지
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• 제25권5호
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• pp.233-237
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• 2015

Silicon oxynitride that can be deposited two times faster than general SiNx:H layer was applied to fabricate the passivation protection layer of atomic layer deposition (ALD) $Al_2O_3$. The protection layer is deposited by plasma-enhanced chemical vapor deposition to protect $Al_2O_3$ passivation layer from a high temperature metallization process for contact firing in screen-printed silicon solar cell. In this study, we studied passivation performance of ALD $Al_2O_3$ film as functions of process temperature and RF plasma effect in plasma-enhanced chemical vapor deposition system. $Al_2O_3$/SiON stacks coated at $400^{\circ}C$ showed higher lifetime values in the as-stacked state. In contrast, a high quality $Al_2O_3$/SiON stack was obtained with a plasma power of 400 W and a capping-deposition temperature of $200^{\circ}C$ after the firing process. The best lifetime was achieved with stack films fired at $850^{\circ}C$. These results demonstrated the potential of the $Al_2O_3/SiON$ passivated layer for crystalline silicon solar cells.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.221-221
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• 2014

The present work proposes an improved numerical simulator for design and modification of large area capacitively coupled plasma (CCP) processing chamber. CCP, as notoriously well-known, demands the tremendously huge computational cost for carrying out transient analyses in realistic multi-dimensional models, because electron dissociations take place in a much smaller time scale (${\Delta}t{\approx}10-8{\sim}10-10$) than time scale of those happened between neutrals (${\Delta}t{\approx}10-1{\sim}10-3$), due to the rf drive frequencies of external electric field. And also, for spatial discretization of electron flux (Je), exponential scheme such as Scharfetter-Gummel method needs to be used in order to alleviate the numerical stiffness and resolve exponential change of spatial distribution of electron temperature (Te) and electron number density (Ne) in the vicinity of electrodes. Due to such computational intractability, it is prohibited to simulate CCP deposition in a three-dimension within acceptable calculation runtimes (<24 h). Under the situation where process conditions require thickness non-uniformity below 5%, however, detailed flow features of reactive gases induced from three-dimensional geometric effects such as gas distribution through the perforated plates (showerhead) should be considered. Without considering plasma chemistry, we therefore simulated flow, temperature and species fields in three-dimensional geometry first, and then, based on that data, boundary conditions of two-dimensional plasma discharge model are set. In the particular case of SiH4-NH3-N2-He CCP discharge to produce deposition of SiNxHy thin film, a cylindrical showerhead electrode reactor was studied by numerical modeling of mass, momentum and energy transports for charged particles in an axi-symmetric geometry. By solving transport equations of electron and radicals simultaneously, we observed that the way how source gases are consumed in the non-isothermal flow field and such consequences on active species production were outlined as playing the leading parts in the processes. As an example of application of the model for the prediction of the deposited thickness uniformity in a 300 mm wafer plasma processing chamber, the results were compared with the experimentally measured deposition profiles along the radius of the wafer varying inter-electrode gap. The simulation results were in good agreement with experimental data.