• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.394-400
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• 2014

In this study, we fabricated ITZO thin films on glass substrates with various RF power from 30 to 60W and investigated the electrical, optical and structural properties. ITZO thin film deposited at 50W exhibited the largest figure of merit ($10.52{\times}10^{-3}{\Omega}^{-1}$) and then its resistivity and sheet resistance were $3.08{\times}10^{-4}{\Omega}-cm$ and $11.41{\Omega}/sq.$, respectively. As results of optical characterization, average transmittance of all ITZO thin films were over 80%. ITZO thin films had amorphous structure regardless of the RF power. The FESEM and AFM results showed that all ITZO thin films have a very smooth surface having no cracks and defects and the film deposited at 50W exhibit the smallest surface roughness of 0.254nm. We found that a amorphous ITZO thin film is a very promising material for replacing ITO in the next display device such as OLED.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.7
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• pp.1285-1290
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• 2017

We prepared ITZO thin films with various thicknesses on glass substrates using RF magnetron sputtering and investigated electrical, optical and structural properties of the thin film. Sheet resistance of ITZO thin film showed a decreasing trend on the increase of film thickness, but its resistivity exhibited a substantially constant value of $5.06{\pm}1.23{\times}10^{-4}{\Omega}-cm$. Transmittance of ITZO thin film moved to the long-wavelength with the increase of film thickness. Figure of merit in a visible light and an absorption area of P3HT:PCBM organic active layer of the 360nm-thick IZTO thin film was $8.21{\times}10^{-3}{\Omega}^{-1}$ and $9.29{\times}10^{-3}{\Omega}^{-1}$, respectively. Through XRD and AFM measurements, it was confirmed that all the ITZO thin films have amorphous structure and the surface roughness of films are very smooth in the range of 0.561 to 0.263 nm. In this study, it was found that amorphous ITZO thin film is a very promising material for organic solar cell.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.6
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• pp.1095-1100
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• 2021

In this study, ITZO thin films were deposited on glass, sapphire, and PEN substrates by RF magnetron sputtering, and their electrical and optical properties were investigated. The resistivity of the ITZO thin film deposited on the glass and sapphire substrates was 3.08×10-4 and 3.21×10-4 Ω-cm, respectively, showing no significant difference, whereas the resistivity of the ITZO thin film deposited on the PEN substrate was 7.36×10-4 Ω-cm, which was a rather large value. Regardless of the type of substrate, there was no significant difference in the average transmittance of the ITZO thin film. Figure of Merits of the ITZO thin film deposited on the glass substrate obtained using the average transmittance in the absorption region of the amorphous silicon thin film solar cell and the absorption region of the P3HT : PCBM organic active layer were 10.52 and 9.28×10-3 Ω-1, respectively, which showed the best values. Through XRD and AFM measurements, it was confirmed that all ITZO thin films exhibited an amorphous structure and had no defects such as pinholes or cracks, regardless of the substrate type.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.252-253
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• 2014

비정질 ITZO 박막은 ITZO(In:Sn:Zn= 8:1:1, 6:2:2, 4:3:3, 2:4:4) 타겟을 이용하여 상온에서 RF 마그네트론 스퍼터링 법으로 제조 되었다. ITZO 박막의 물성을 알아보기 위하여 조성별, 산소 분압별 및 열처리에 따른 박막의 구조적, 전기적, 광학적 특성을 분석하였다. 박막 실험 결과를 바탕으로 ITZO(4:3:3) 박막을 채널 층으로 이용하여 성공적으로 박막 트랜지스터를 제작 하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.887-892
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• 2019

In this study, after 20nm-thick $SiO_2$ thin film was deposited by PECVD method on the PES substrate, which is known to have the highest heat resistance among plastic substrates, as a buffer layer, ITZO thin films were deposited by RF magnetron sputtering method to investigate the electrical and optical properties according to the working pressure. The ITZO thin film deposited at the working pressure of 3mTorr showed the best electrical properties with a resistivity of $8.02{\times}10^{-4}{\Omega}-cm$ and a sheet resistance of $50.13{\Omega}/sq.$. The average transmittance in the visible region (400-800nm) of all ITZO films was over 80% regardless of working pressure. The Figure of merit showed the largest value of $23.90{\times}10^{-4}{\Omega}^{-1}$ in the ITZO thin film deposited at 3mTorr. This study found that ITZO thin films are very promising materials to replace ITO thin films in next-generation flexible display devices.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1873-1878
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• 2013

ITZO ($In_2O_3$ : $SnO_2$ : ZnO = 90wt.% : 5wt.% : 5wt.%) thin films were fabricated on glass substrates (Eagle 2000) at room temperature with various working pressures (1~7 mTorr) by RF magnetron sputtering. The influence of the working pressure on the structural, electrical, and optical properties of the ITZO thin films were investigated. The XRD and FESEM results showed that all ITZO thin films are amorphous structures with very smooth surfaces regardless of the working pressure. Amorphous ITZO thin films deposited at 3 mTorr showed the best properties, such as a low resistivity, high transmittance, and figure of merit of $3.08{\times}10^{-4}{\Omega}{\cdot}cm$, 81 %, and $10.52{\times}10^{-3}{\Omega}^{-1}$, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.212.2-212.2
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• 2015

본 연구에서는 용액 공정을 통해 제작한 IGZO, ITZO 박막 트랜지스터의 전기적 특성을 비교, 분석하였다. 실험에 사용된 용액의 농도는 In:Zn:Ga, In:Zn:Sn = 1:1:1로 제작하여 Spin-Coating을 통해 증착하였다. 두 소자 모두 $350^{\circ}C$에서 열처리 공정을 진행한 뒤, 전기적 특성을 측정 및 분석하였다. IGZO 박막 트랜지스터의 경우, Threshold Voltage, S.Swing, Mobility, On/Off ratio가 각각 2.2 V, 0.42, $0.18cm^2/Vs$, $1.5{\times}$10^5로 측정되었으나 ITZO 박막 트랜지스터의 경우, -6.92 V, 0.91, $0.43cm^2/Vs$, $2.1{\times}$10^5 로 IGZO보다 Negative한 방향으로 이동하였다. 이는 Sn이 Ga에 비해 Band gap이 넓고, 산소와의 결합력이 작기 때문에, ITZO 박막 트랜지스터가 Oxygen vacancy형성을 통한 Carrier density가 높은 것으로 판단된다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.195-196
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• 2009

ITZO 박막과 $TIO_2$ 버퍼층은 각각 두 개의 캐소드를 사용한 마그네트론 2원동시 방전법과 산소 함량 2%를 사용한 반응성 sputtering 방법으로 각각 증착이 되었다. 모든 박막들은 상온에서 폴리머 기판인 PET에 증착되었다. $TiO_2$ 버퍼층을 도입함으로써 ITZO/$TiO_2$ 박막은 비정질 구조를 보여 주었고, 그것들의 비저항은 버퍼층의 두께가 증가할수록 감소함을 관찰하였다. 특히 기계적 특징은 $TiO_2$ 버퍼층을 5nm 증착하였을 경우에 bending test와 광학 현미경의 crack정도를 관찰함으로써 향상되었음을 확인할 수 있었다. 투과율에 있어서 단일 ITZO 박막과 버퍼층을 5nm 도입한 박막은 가시광선에서 약 75%의 투과율을 가짐을 알 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.242.2-242.2
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• 2013

최근 산화물 반도체 박막 트랜지스터의 신뢰성(reliability) 평가에 대한 연구가 활발히 이루어지고 있다. 신뢰성 평가하는 한 방법으로 게이트에 바이어스를 지속적으로 인가하여 소자의 문턱 전압의 변화를 통해 안정성(stability)를 확인한다. 전압을 지속적으로 인가하게 되면 소자를 열화시켜 전기적 특성이 약화된다. 본 연구에선 ITZO 박막 트랜지스터의 신뢰성 평가를 위해 게이트 절연막($SiO_2$, $SiN_x$)에 따른 ITZO 소자를 제작 및 게이트 바이어스 스트레스 후 전기적 특성을 비교, 분석하였다. 제작된 소자의 게이트에 전압을 +15V로 7200초 동안 인가하였다. 스트레스 후 게이트 절연막이 $SiO_2$, $SiN_x$인 ITZO 산화물 박막 트랜지스터 모두 positive 방향으로 이동하였고, 그 결과 문턱 전압, 이동도, 아문턱 기울기의 변화가 발생하였다. $SiO_2$의 경우 아문턱 기울기의 변화가 거의 없이 문턱 전압의 변화만을 보였고, 이는 단순히 ITZO층과 게이트 절연막 계면에 전자가 포획되거나 혹은 게이트 절연막 내에 전자가 주입이 되었기 때문이다. 반면에 $SiN_x$의 경우 ITZO층과 게이트 절연막 계면에 추가적인 결함(defect)이 생성되었기 때문에 $SiO_2$보다 더 많은 전자를 포획하여 아문턱 기울기와 문턱 전압의 변화가 컸다.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.3
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• pp.443-450
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• 2021

After selecting a PES substrate with excellent thermal stability and optical properties among plastic substrates, a SiO₂ thin film was deposited as a buffer layer to a thickness of 20nm by plasma-enhanced chemical vapor deposition to compensate for the high moisture absorption. Then, the ITZO thin film was deposited by a RF magnetron sputtering method to investigate electrical and optical properties according to RF power. The ITZO thin film deposited at 50W showed the best electrical properties such as a resistivity of 8.02×10^-4 Ω-cm and a sheet resistance of 50.13Ω/sq.. The average transmittance of the ITZO thin film in the visible light region(400-800nm) was relatively high as 80% or more when the RF power was 40 and 50W. Figure of Merits (Φ_TC and FOM) showed the largest values of 23.90×10^-4 Ω^-1 and 5883 Ω^-1cm^-1, respectively, in the ITZO thin film deposited at 50W.