• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.55-55
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• 2018

Recently, amorphous oxides such as InGaZnO (IGZO) and InZnO (IZO) as a channel layer of an oxide TFT have been attracted by advantages such as high mobility, good uniformity, and high transparency. In order to apply such an amorphous oxide TFTs to a display, the stability in various environments must be ensured. In the InGaZnO which has been studied in the past, Ga elements act as a suppressor of oxygen vacancy and result in a decreased mobility at the same time. Previous studies have been showed that the InZnO, which does not contain Ga, can achieve high mobility, but has relatively poor stability under various instability environments. In this study, the TFTs using $IZO/Al_2O_3$ double layer structure were studied. The introduction of an $Al_2O_3$ interlayer between source/drain and channel causes superior electrical characteristics and electrical stability as well as reduced contact resistance with optimally perfect ohmic contact. For the IZO and $Al_2O_3$ bilayer structures, the IZO 30nm IZO channels were prepared at $Ar:O_2=30:1$ by sputtering and the $Al_2O_3$ interlayer were depostied with various thickness by ALD at $150^{\circ}C$. The optimal sample exhibits considerably good TFT performance with $V_{th}$ of -3.3V and field effect mobility of $19.25cm^2/Vs$, and reduced $V_{th}$ shift under positive bias stress stability, compared to conventional IZO TFT. The enhanced TFT performances are closely related to the nice ohmic contact properties coming from the defect passivation of the IZO surface inducing charge traps, and we will provide the detail mechanism and model via electrical analysis and transmission line method.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.114.2-114.2
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• 2017

Transparent film heaters (TFHs) based on Joule heating are currently an active research area. However, TFHs based on an indium tin oxide (ITO) monolayer have a number of problems. For example, heating is concentrated in part of the device. Also, heating efficiency is low because it has high sheet resistance ($R_S$). Resistance of indium zinc oxide (IZO) is similar to ITO and it can be used to flexible applications due to its amorphous structure. To solve these problems, our study introduced hybrid layers of IZO/Ag/IZO deposited by magnetron sputtering, and the electrical, optical, and thermal properties were estimated for various thickness of the metal interlayer. It was found that the sheet resistance of the multilayer was mainly dependent on the thickness of the Ag layers. The $R_S$ of IZO(40)/Ag/IZO(40nm) multilayer was 5.33, 3.29, $2.15{\Omega}/{\Box}$ for Ag thickness of 10, 15, and 20nm, respectively, while the $R_S$ of an IZO monolayer(95nm) was $59.58{\Omega}/{\Box}$. The optical transmittance at 550nm for the IZO(95nm) monolayer is 81.6%, and for the IZO(40)/Ag/IZO(40nm) multilayers with Ag thickness 10, 15 and 20nm, is for 72.8, 78.6, and 63.9%, respectively. The defrost test showed that the film with the lowest RS had the highest heat generation rate (HGR) for the same applied voltage. The results indicated that IZO(40)/Ag(15)/IZO(40nm) multilayer has the best suitable property, which is a promising thin film heater for the application in vehicle windshield.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1425-1428
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• 2007

The amorphous IZO on flexible substrate (PC) shows similar electrical conductivity and optical transmittance with commercial ITO glass even though it was prepared at $<50\;^{\circ}C$. Moreover, it exhibits little resistance change during 5000 bending cycles, demonstrating good mechanical robustness. A green phosphorescent OLED fabricated on amorphous IZO on flexible PC shows maximum external quantum efficiency of ${\eta}_{ext}=13.7\;%$ and power efficiency of ${\eta}_p=32.7\;lm/W$, which are higher than a device fabricated on a commercial ITO on glass (${\eta}_{ext}=12.4%$ and ${\eta}_p=30.1\;lm/W$) and ITO on flexible PC (${\eta}_{ext}=8.5%$ and ${\eta}_p=14.1\;lm/W$).

• 한국표면공학회지
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• 제40권6호
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• pp.245-249
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• 2007

Amorphous IZO films were deposited on PET substrate by DC magnetron sputtering without substrate heating. In order to investigate effect of reactive gas addition on film properties, 0.2-0.4% of $H_2$ or $O_2$ gas was introduced during the deposition. Deposited IZO films were evaluated with mechanical property, electrical property, and water permeability. In the case of $H_2$ gas addition, mechanical property showed clear degradation compared to $O_2$ gas. In the case of $O_2$ gas, water permeability of the IZO film was increased compared to $H_2$ gas which could be attributed to the low adhesion of the film caused by bombardment of high energy negative oxygen ion. As a result, it is confirmed that water permeability of the film could be strongly affected by adhesion of the film.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2014년도 추계학술대회 논문집
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• pp.237-238
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• 2014

비정질 투명 전도성 산화물의 전기적 특성을 개선하기 위해 불순물 도입을 통한 연구가 많이 진행되고 있다. 하지만 50 nm의 박막 두께에서는 물론, 얇은 박막 두께에 맞춰 극미량의 Sn 첨가를 통한 4성분계 IZO에 대한 연구는 보고된 바 없다. 본 연구에서는 DC 마그네트론 스퍼터링 법을 이용하여 Sn을 미량 도핑 한 50 nm IZO 박막을 제조하였으며, 후열처리 전후의 전기적, 기계적, 광학성 특성을 비교 분석 하였다. Sn이 미량 도핑 되었을 때 전기적 특성이 개선되었고, 이러한 현상은 후열처리 온도에 따라 뚜렷하게 관찰되었다. 이것은 불순물 Sn이 전기적으로 활성화되었기 때문이라고 생각된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.405-406
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• 2008

The amorphous indium zinc oxide (IZO) thin films were deposited on polyethersulfone (PES) and glass substrates by facing targets sputtering. IZO thin films deposited as functions of gas flow ratio on PES and glass substrates, respectively. The electrical, optical and structural properties of IZO thin films were evaluated by a Hall Effect Measurement, an X-Ray Diffractormeter, UV/VIS spectrometer in visible range and a scanning electron microscopy, respectively. As-deposited IZO thin films exhibited resistivity of $5.4\times10^{-4}$ and $4.5\times10^{-4}$ [$\Omega$-cm] on PES and glass substrates, respectively. The optical transmittance showed over 85% in the visible region on PES and glass substrates.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.406-407
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• 2007

We prepared indium zinc oxide (IZO) thin film for cathode electrode such as an application of flat panel display by using the facing targets sputtering (FTS) method at room temperature. The effects of input power and film thickness were investigated with respect to physical and optical properties of films such as deposition rate, electrical properties, microstructure and transmittance. We could obtain properties of IZO thin films of under $10^{-3}\;{\Omega}-cm$ in resistivity and the thin films of over 90% in transmittance. Also, we obtained IZO thin films which were an amorphous structure.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.225-225
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• 2011

The dielectric and optical properties of GaInZnO (GIZO), HfInZnO (HIZO) and InZnO (IZO) thin films on glass by RF magnetron sputtering method were investiged using reflection electron energy loss spectroscopy (REELS). The band gap was estimated from the onset values of REELS spectra. The band gaps of GIZO, HIZO and IZO thin films are 3.1 eV, 3.5 eV and 3.0 eV, respectively, Hf and Ga incorporated into IZO results in an increase in the energy band gap of IZO by 0.5 eV and 0.1 eV. The dielectric functions were determined by comparing the effective cross section determined from experimental REELS with a rigorous model calculation based on the dielectric response theory, using available software package, good agreement between the experimental and fitting results gives confidence in the accuracy of the determined dielectric function. The main peak of Energy Loss Function (ELF) obtained from IZO shows at 18.42 eV, which shifted to 19.43 eV and 18.15 eV for GIZO and HIZO respectively, because indicates the corporation of cation Ga and Hf in the composition. The optical properties represented by the dielectric function e, the refractive index n, the extinction coefficient k, and the transmission coefficient, T of HIZO and IZO thin films were determined from a quantitative analysis of REELS. The transmission coefficient was increased to 93% and decreased to 87% in the visible region with the incorporation of Hf and Ga in the IZO compound.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.379-380
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• 2007

The characteristics of a co-sputtered indium zinc tin oxide (IZTO) films prepared by dual target dc magnetron sputtering from IZO and ITO targets at a room temperature are investigated. Film properties, such as sheet resistance, optical transmittance, surface work function and surface roughness were examined as a function of ITO dc power at constant IZO dc power of 100 W. It was shown that the increase of the ITO dc power during co-sputtering of ITO and IZO target resulted in an increase of sheet resistance of the IZTO films. This can be attributed to high resistivity of ITO film prepared at room temperature. Surface smoothness and roughness were investigated by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The synchrotron x-ray scattering results obtained from IZTO film with different ITO contents showed that introduction of ITO atoms into amorphous IZO film resulted in a crystallization of IZTO film with (222) preferred orientation due to low alc transition temperature of ITO film. However, the transmittance of the IZTO films with thickness of 150 nm is between 80 and 85 % at wavelength of 550 nm regardless of ITO content. Possible mechanism to explain the ITO and IZO co-sputtering effect on properties of IZTO is suggested.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 추계학술발표대회 및
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• pp.76.2-76.2
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• 2007