• Current Photovoltaic Research
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• v.2 no.3
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• pp.88-94
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• 2014

The structural, optical and electrical properties of sputter-deposited CIGS films were directly influenced by the sputtering process parameters such as substrate temperature, working pressure, RF power and distance between target and substrate. CIGS thin films deposited by using a quaternary target revealed to be Se deficient due to Se low vapor pressure. This Se deficiency affected the overall stoichiometry of the films, causing the films to be Cu-rich. Current tends to pass through the Cu-Se channels which act as the shunting path increasing the film conductivity. The crystal structure of CIGS thin films depends on the substrate orientation due to the influence of surface morphology, grain size and stress of Mo substrate. The excess of Cu was removed from the CIGS films by KCN treatment, achieving a suitable Cu concentration (referred as Cu-poor) for the fabrication of solar cell. Due to high Cu concentrations on the CIGS film surface induced by Cu-Se phases after CIGS film deposition, KCN treatment proved to be necessary for the fabrication of high efficiency solar cells. Also during KCN treatment, dislocation density and lattice parameter decreased as excess Cu was removed, resulting in increase of bandgap and the decrease of conductivity of CIGS films. It was revealed that Cu-Se secondary phase could be removed by KCN wet etching of CIGS films, allowing the fabrication of high efficiency absorber layer.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.1
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• pp.143-152
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• 2003

The aims of the present study was to observe resin tag of the resin/enamel, dentin interface produced by self-etching adhesive systems and evaluate effect of additional acid etching on resin tag formation. Three self-etching primer(SE bond, AQ bond and L Pop) and an one bottle adhesive(Single bond) were used. Flat occlusal enamel and dentin disks were obtained from extracted human molars. A total of 20 surfaces were collected and divided into four groups of 5 samples. One-half of each specimen in each group was etched with 35% phosphoric acid prior to the application of each adhesive system, with the second half being kept unetched. Subsequently, resin composite was placed and polymerized. The samples were sliced and immersed into HCl and NaOCl solutions, followed by drying and sputter coating for examination with a SEM. The results were as follows; 1. Additional etching side of dentin displayed longer and thicker resin tag than unetched side in all self-etching adhesive groups. 2. In enamel, additional etching side displayed deeper and more distinct etching pattern than unetched side except L Pop. There is no difference between etched and unetched enamel in L Pop. The results obtained suggest the self-etching adhesive did not etch enamel and penetrate into dentinal tubule as deeply as did additional etching. Further research should include the evaluation of the relationship of boding strength, microleakage and resin tag morphology.

• Journal of the Korean institute of surface engineering
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• v.42 no.5
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• pp.216-219
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• 2009

A surface acoustic wave (SAW) filter structure was fabricated employing $4{\mu}m$ thick nanocrystalline diamond (NCD) and $2.2{\mu}m$ thick ZnO films on Si wafer. The NCD film was deposited in an $Ar/CH_4$ gas mixture by microwave plasma chemical vapor deposition method. The ZnO film was formed over the NCD film in an RF magnetron sputter using ZnO target and $Ar/O_2$ gas. On the top of the two layers, copper film was deposited by the RF sputter and inter digital transducer (IDT) electrode pattern (line/space : $1.5/1.5{\mu}m$) was defined by the photolithography including a lift-off etching process. The fabricated SAW filter exhibited the center frequency of 1.66 GHz and the phase velocity of 9,960 m/s, which demonstrated that a giga Hertz SAW filter can be realized by utilizing the nanocrystalline diamond thin film.

• Korean Journal of Materials Research
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• v.2 no.6
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• pp.443-451
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• 1992

Effects of various pretreatments on the nucleation of CVD-W deposited on the reactively sputter-deposited TiN was investigated. Incubation period of nucleation and deposition rate decreased by the pretreatment of Ar rf-sputter etching for the depth below 300k, but they increased for the etchig depth over 200A. The preteatment of Ar ion implantation decreased the incubation period of nucleation, but increased deposition rate. Also Si$H_4$flushing pretreatment decreased the incubation period of nucleation slightly due to the absorption of Si by TiN surface.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.3
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• pp.15-19
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• 2003

In This paper, we developed 1.96 GHz air gap type FBAR BPF using ZnO as piezoelectric sputtered by RF magnetron at room temperature. FBAR BPF was fabricated by sputtering bottom electrode (Al), ZnO as piezoelectric and top electrode (Mo) on Si wafer one by one with RF magnetron sputter, then Si was dry etched to make an air hole. XRD test result of fabricated FBAR BPF showed that ZnO crystal was well pre-oriented as (002) and sigma value of XRC was 1.018. IL(Insertion loss) showed excellent result as 1 dB.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.20-20
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• 1998

I Ion beam technology has recently attracted much interest because it has exciting t technological p아:ential for surface analysis, ion beam mixing, surface cleaning and etching i in thin film growth and semiconductor fabrication processes, etc. Es야~cially, ion beam s sputtering has been widely used for sputter depth profiling with x-photoelectron S spectroscopy (XPS) , Auger electron s$\pi$~troscopy(AES), and secondary-ion mass S야i따oscopy(SIMS). However, The problem of surface compositional ch없1ge due to ion b bombardment remains to be understo여 없ld solved. So far sputtering processes have been s studied by s따face an외ysis tools such as XPS, AES, and SIMS which use the sputtering p process again. It would be improbable to measure the modified surface composition profiles a accurately due to ion beam bombardment with surface analysis techniques based on sputter d depth profiling. However, recently Medium energy ion scattering spectroscopy(MEIS) has b been applied to study the sputtering of solid surface at ion bombardment and has been p proved that it has been extremely valuable in probing the surface composition 뻐d s structure nondestructively and quantita디vely with less than 1.0 nm depth resolution. To u understand the sputtering processes of solid surface at ion bombardment, The Molecular D Dynamics(MD) and Monte Carlo(MC) simulation has been used and give an intimate i insight into the sputtering processes of solid surfaces. In this presentation, the sputtering processes of alloys and compound samples at ion b bombardment will be reviewed and the MEIS results for the Ar+ sputter induced altered l layer of the TazOs thin film 뻐dd없nage profiling of Ar+ ion sputt얹"ed Si(100) surface will b be discussed with the results of MD and MC simulation.tion.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.795-797
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• 2010

습식 식각은 식각용액으로서 화학용액을 사용하는 공정으로 반응물이 기판표면에서 화학반응을 일으켜 표면을 식각하는 과정이며, 표면결합의 제거를 위한 식각연마와 폴리싱을 위한 식각, 그리고 구조적 형상 패턴등이 있다. 여기서 화학용액은 산화제 또는 환원제 역할을 하는 혼합용액으로 구성된다. 습식 식각 시 수${\mu}m$의 해상도를 얻기 위해서는 그 부식액의 조성이나, 에칭시간, 부식액의 온도 등을 고려하여야 한다. 또한 습식 식각 후 포토 레지스트를 제거하는 과정에서 포토 레지스트를 깨끗이 제거해야 하며, 제거공정 자체가 a-Si:H 박막을 부식 하지 않을 조건으로 행하여야 한다. 포토레지스트 제거 후 잔류 포토 레지스트를 제거하기 위해서 본 실험에서는 RCA-I 세척 기법을 사용한 후 D.I 로 린스 하였다. 본 실험에서 사용한 금속은 Cr, Al, ITO 로 모두 DC sputter 방법을 사용해서 증착하여 사용하였다. Cr박막은 $1300\AA$ 정도의 두께를 사용하였고, ITO (Indium Tin Oxide) 박막은 가시광 영역에서 투명하고 (80% 이상의 transmittance), 저저항 (Sheet Resistance : $50{\Omega}/sq$ 이하) 인 박막을 사용하였으며, 신호선으로 주로 사용되는 Al등의 증착조건에 따른 wet etching 특성을 조사하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.363-363
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• 2008

The development of dry etching process for sapphire wafer with plasma has been key issues for the opto-electric devices. The challenges are increasing control and obtaining low plasma induced-damage because an unwanted scattering of radiation is caused by the spatial disorder of pattern and variation of surface roughness. The plasma-induced damages during plasma etching process can be classified as impurity contamination of residual etch products or bonding disruption in lattice due to charged particle bombardment. Therefor, fine pattern technology with low damaged etching process and high etch rate are urgently needed. Until now, there are a lot of reports on the etching of sapphire wafer with using $Cl_2$/Ar, $BCl_3$/Ar, HBr/Ar and so on [1]. However, the etch behavior of sapphire wafer have investigated with variation of only one parameter while other parameters are fixed. In this study, we investigated the effect of pressure and other parameters on the etch rate and the selectivity. We selected $BCl_3$ as an etch ant because $BCl_3$ plasmas are widely used in etching process of oxide materials. In plasma, the $BCl_3$ molecule can be dissociated into B radical, $B^+$ ion, Cl radical and $Cl^+$ ion. However, the $BCl_3$ molecule can be dissociated into B radical or $B^+$ ion easier than Cl radical or $Cl^+$ ion. First, we evaluated the etch behaviors of sapphire wafer in $BCl_3$/additive gases (Ar, $N_2,Cl_2$) gases. The behavior of etch rate of sapphire substrate was monitored as a function of additive gas ratio to $BCl_3$ based plasma, total flow rate, r.f. power, d.c. bias under different pressures of 5 mTorr, 10 mTorr, 20 mTorr and 30 mTorr. The etch rates of sapphire wafer, $SiO_2$ and PR were measured with using alpha step surface profiler. In order to understand the changes of radicals, volume density of Cl, B radical and BCl molecule were investigated with optical emission spectroscopy (OES). The chemical states of $Al_2O_3$ thin films were studied with energy dispersive X-ray (EDX) and depth profile anlysis of auger electron spectroscopy (AES). The enhancement of sapphire substrate can be explained by the reactive ion etching mechanism with the competition of the formation of volatile $AlCl_3$, $Al_2Cl_6$ or $BOCl_3$ and the sputter effect by energetic ions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.414-414
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• 2009

나노스피어 리소그래피는 기존의 리소그래피 방법에 비해 나노 크기 패턴을 제작하는데 공정이 간단하며 재현성있게 대면적에 패터닝이 가능하다는 장점이 있다. 본 연구에서는 Vertical LED(V-LED)의 External quantum efficiency 향상을 위하여 나노스피어 리소그래 피를 이용하여 V-LED의 n-GaN 표면을 패터닝을 하였다. n-GaN 위에 Sputter를 이용하여 $SiO_2$를 증착 후 나노스피어를 스핀 코팅을 이용하여 단일막을 형성하였다. 그 후, 반응성 이온 식각 장치를 이용하여 나노스피어의 크기를 조절하고 $SiO_2$층을 식각하였다. 다음과 같은 공정 후 $SiO_2$층을 Mask층으로 하여 n-GaN 표면을 식각하였다. 실험 결과 나노스피어 리소그래피를 이용하여 V-LED의 External quantum efficiency 향상을 위한 n-GaN 표면의 패턴 제작이 가능함을 확인할 수 있었다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.115-121
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• 1995

A mask for x-ray lithography is fabricated with SiN membrane and WTi absorber. SiN membrane is deposited by plasma enhanced chemical vapor deposition, and the stress of SiN membrane is controlled to be less than 100 MPa by rapid thermal annealing. WTi absorber is reactively deposited by DC-magnetron type sputter, and the working gases are argon and nitrogen. Added nitrogen is contributed to the stress of WTi absorber. The stress of WTi absorber is controlled to be less than $\pm$ 100 MPa by controlling the deposition pressure. 10$\mu$m WTi pattern is delineated on SiN membrane by dry etching technique.