• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.332-335
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• 2020

Drop casting, a solution process, is a simple low-cost fabrication technique that does not waste material. In this study, we elucidate the effect of the concentration of a InGaZnO solution on the electrical properties of drop-cast oxide thin-film transistors. The higher the concentration the larger the amount of remnant InGaZnO solutes, which yields a thicker thin film. Accordingly, the electrical properties were strongly dependent on the concentration. At a high concentration of 0.3 M (or higher), a large current flowed but did not lead to switching characteristics. At a concentration lower than 0.01 M, switching characteristics were observed, but the mobility was small. In addition to a high mobility, sufficient switching characteristics were obtained at a concentration of 0.1 M owing to the appropriate thickness of the semiconductor layer. This study provides a technical basis for the low-cost fabrication of switching devices capable of driving a sensor array.

• Korean Journal of Materials Research
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• v.17 no.6
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• pp.308-312
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• 2007

Chromium oxide thin films have been deposited on silicon substrates using a tabletop 9kJ mathertyped plasma focus (PF) device. Before deposition, pinch behavior with gas pressure was observed. Strength of pinches was increased with increasing working pressure. Deposition was performed at room temperature as a function of working pressure between 50 and 1000 mTorr. Composition and surface morphology of the films were analyzed by Auger Electron Spectroscopy and Scanning Electron Microscope, respectively. Growth rates of the films were decreased with pressure. The oxide films were polycrystalline containing some impurities, Cu, Fe, C and revealed finer grain structure at lower pressure.

• Journal of the Korean Vacuum Society
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• v.11 no.1
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• pp.16-21
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• 2002

Selective epitaxial growth(SEG) of silicon were performed at low temperature under an ultraclean environment below $1000^{\circ}C$ using ultraclean $Si_2H_6$ and $H_2$ gases ambient in low pressure chemical vapor deposition(LPCVD). As a result of ultraclean processing, epitaxial Si layers with good quality were obtained for uniform and SEG wafer at temperatures range 600~$710^{\circ}C$ and an incubation period of Si deposition only on $SiO_2$ was found. Low-temperature Si selectivity deposition condition and epitaxy on Si were achieved without addition of HCl. The epitaxial layer was found to be thicker than the poly layer deposited over the oxide. Incubation period prolonged for 20~30 sec can be obtained by $O_2$addition. The surface morphologies & cross sections of the deposited films were observed with SEM, The structure of the Si films was evaluated XRD.

• Korean Journal of Materials Research
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• v.7 no.8
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• pp.694-700
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• 1997

TiC(001) 면위에 Mg 금속을 단원자층으로 증착시킨 후 산화 및 열처리 과정을 거쳐서 MgO 초박막을 성장시키고, 성장된 MgO 막의 전자상태 및 표면포논을 UPS, XPS 및 HREELS를 사용하여 측정하였다. 전도성 기판위에 epitaxial 산화물막을 성장시킨 후 성장된 막의 전자구조 및 표면포논을 측정함으로써 벌크에서 분리된 2차원적 특성을 갖는 '표면 모델'의 물성을 연구하고자 하였는데, 이러한 '표면모델'은 잘 배열된 원자구조를 얻을 수 있고 두께가 충분히 얇아서 전하축적을 피할 수 있기 때문이다. 기판으로는 MgO와 같은 암염형 결정구조를 갖고 있고, 격자상수 차이가 2.6% 로서 매우 작으며, 비저항이 매우 낮은 전이 금속 탄화물 중의 하나인 TiC(001) 면을 사용하였다. TiC(001)면에 증착된 MgO층의 UPS He-l 스펙트럼을 측정한 결과 O2p및 XPS스펙트럼은 열처리를 전후로 하여 변하지 않았으며, 이로부터 상온에서 산소의 확산만으로 MgO 상이 형성됨을 알 수 있었다. MgO초박막의 표면 포논을 HREELS를 사용하여 검출하였다. 거시적 포논중에서 F-K 파 및 Rayleigh 모드가 관찰되었는데, F-k파는 MgO막의 2차원성으로 인하여 벌크의 경우보다 높은 진동 에너지를 갖고 있었고 Rayleigh모드는 벌크 MgO와 유사한 분산관계를 보였다. 미시적 포논중에서 Wallis(S/sub 2/)모드가 측정되었는데, 그 진동에너지는 벌크에서와 같고 off-specular방향에서도 소멸되지 않았다.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.251-257
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• 2009

In this study, we fabricated nickel oxide thin film for lithium based electrolyte using sol-gel method. This film was deposited by dip-coating method with mixed solvent of DameH (N,N-dimethylaminoethanol) and DI water. As changing the ratio between DmaeH and DI water, nickel oxide thin film was presented in different charge density and optical transmittance because they were shown various thickness. It was accounted for changing viscosity and density by the ratio of DmaeH and DI water. The thin film synthesized with 1 : 1 ratio of DmaeH and DI water was expressed best electrochromic performance in lithium based electrolyte, because of thick thickness but porous structures.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.12-12
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• 2010

Time dependence of the shift of the threshold voltage of amorphous hafnium-indium-zinc oxide (a-HIZO) has been reported under on-current stress condition. a-HIZO thin films were deposited on $SiO_2$/Si (100) by rf magnetron sputtering. XPS measurement indicates that the Hf metal cations in a-HIZO system after annealing process reduce oxygen vacancies by binding oxygen. It was found that the Hf metal cation can be effectively incorporated in the IZO thin films as a suppressor against both the oxygen deficiencies and the carrier generation in the ZnO-based system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.391-391
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• 2010

The stability enhancement of Znic oxide thin film transistor deposited by PLD-DBD has been reported here using the bias temperature stress test. Znic oxide (ZnO) thin films were deposited on $SiO_2$/Si (100) by pulsed laser deposition method with and without dielectric barrier discharge (DBD) method. The DBD is the efficient method to adopt the nitrogen ions into the thin films. The TFT characteristics of ZnO TFTs with and without Nirogen (N) doping show similar results with $I_{on/off}$ of $10^5{\sim}10^6$. However. the bias temperature stress (BTS) test of N-doped ZnO TFT with DBD shows higher stability than that of ZnO TFT.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.10
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• pp.651-655
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• 2017

This work reports the surface morphology and transmittance of copper oxide thin films for semitransparent solar cell applications. We prepared the oxide specimens by subjecting copper thin films to an oxidation reaction at annealing temperatures ranging between $100^{\circ}C$ and $300^{\circ}C$. The color of the as-deposited specimen was red, but changed to purple at the annealing temperature of $300^{\circ}C$. The surface morphology and transmittance of the specimens were significantly dependent on the annealing temperature and thickness of the copper films. Copper oxide nanoparticles prepared from a 20-nm-thick copper film at an annealing temperature of $300^{\circ}C$ provided a maximum transmittance of 93%. The obtained optical characteristics and surface morphology suggest that copper oxide thin films prepared by an oxidation reaction can be potentially employed as color- and transmittance-adjusting layer in semitransparent thin solar cells.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.7
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• pp.432-436
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• 2017

IZO transistors with $Al_2O_3$ as gate dielectrics have been investigated. To improve permittivity in an ambient dielectric layer, we grew $Al_2O_3$ by atomic layer deposition directly onto the substrates. Then, we prepared IZO semiconductor solutions with 0.1 M indium nitrate hydrate [$In(NO_3)_3{\cdot}xH_2O$] and 0.1 M zinc acetate dehydrate [$Zn(CH_3COO)_2{\cdot}2H_2O$] as precursor solutions; the IZO solution made with a molar ratio of 7:3 was then prepared. It has been found that these oxide transistors exhibit low operating voltage, good turn-on voltage, and an average field-effect mobility of $0.90cm^2/Vs$ in ambient conditions. Studies of low-voltage driving of IZO transistors with atomic layer-deposited high-k $Al_2O_3$ as gate dielectric provide data of relevance for the potential use of these materials and this technology in transparent display devices and displays.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.7
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• pp.437-440
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• 2017

We report on amorphous thin-film transistors (TFTs) with indium zinc oxide (IZO) channel layers that were fabricated via a solution process. We prepared the IZO semiconductor solution with 0.1 M indium nitrate hydrate and 0.1 M zinc acetate dehydrate as precursor solutions. The solution- processed IZO TFTs showed good performance: a field-effect mobility of $7.29cm^2/Vs$, a threshold voltage of 4.66 V, a subthreshold slope of 0.48 V/dec, and a current on-to-off ratio of $1.62{\times}10^5$. To investigate the static response of our solution-processed IZO TFTs, simple resistor load-type inverters were fabricated by connecting a $2-M{\Omega}$ resistor. Our IZOTFTbased N-MOS inverter performed well at operating voltage, and therefore, isa good candidate for advanced logic circuits and display backplane.