• Electrical & Electronic Materials
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• v.8 no.1
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• pp.21-26
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• 1995

Highly sensitive and mechanically stable gas sensors have been fabricated using the microfabrication and micromaching techniques. The sensing material used to detect the offensive trimethylarnine ((CH$_{3}$)$_{3}$N) gas is 6 wt% $Al_{2}$O$_{3}$-doped, 1000.angs.-thick ZnO deposited by r. f. magnetron sputtering. The optimum operating temperature of the sensor is 350.deg.C and the corresponding heater power is about 85mW. Excellent thermal insulation is achieved by the use of a double-layer structure of 0.2.mu.m -thick silicon nitride and 1.4.mu.m-thick phosphosilicate glass(PSG) prepared by low pressure chemical vapor deposition(LPCVD) and atmospheric pressure chemical vapor deposition(APCVD), respectively. The sensors are mechanically stable enough to endure at least 43, 200 heat cycles between room temperature and 350.deg. C.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.527-530
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• 2009

We report on the fabrication of ZnO-based dual gate (DG) thin-film transistors (TFTs) with 20 nm-thick $Al_2O_3$ for both top and bottom dielectrics, which were deposited by atomic layer deposition on glass substrates at $200^{\circ}C$. Whether top or bottom gate is biased for sweep, our TFT almost symmetrically operates under a low voltage of 5 V showing a field mobility of ~0.4 $cm^2/V{\cdot}s$ along with the on/off ratio of $5{\times}10^4$. The threshold voltage of our DG TFT was systematically controlled from 0.5 to 2.0 V by varying counter gate input from +5 to -2 V.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.932-934
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• 2003

For the insulator of inorganic thin film electroluminescent (TFEL), devices AlON combined with TiON was used and it exhibits higher luminance than AlON as well as $Al_{2}O_{3}$ insulator. Furthermore, using AlON with TiON film show better stability and higher luminance than that with $TiO_{2}$ grown by conventional atomic layer deposition (ALD) for the application of the insulator of ZnS:Mn TFEL device.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.421.1-421.1
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• 2016

We studied indium-doped zinc oxide (IZO) film grown by atomic layer deposition (ALD) as transparent conductive oxide (TCO). A variety of TCO layer, such as ZnO:Al (AZO), InSnO2(ITO), Zn (O,S) etc, has been grown by various method, such as ALD, chemical vapor deposition (CVD), sputtering, laser ablation, sol-gel technique, etc. Among many deposition methods, ALD has various advantages such as uniformity of film thickness, film composition, conformality, and low temperature deposition, as compared with other techniques. In this study, we deposited indium-doped zinc oxide thin films using diethyl[bis(trimethylsilyl)amido]indium [Et2InN(TMS)2] as indium precursor, DEZn as zinc precursor and H2O as oxidant for ALD and investigated the optical and electrical properties of IZO films. As an alternative, this liquid In precursor would has several advantages in indium oxide thin-film processes by ALD, especially for low resistance indium oxide thin film and high deposition rate as compared to InCp, InCl3, TMIn precursors etc. We found out that Indium oxide films grown by Et2InN(TMS)2 and H2O precursor show ALD growth mode and ALD growth window. We also found out the different growth rate of Indium oxide as the substrate and investigated the effect of the substrate on Indium oxide growth.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.461-463
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• 2009

We report on the fabrication of ZnO-based thin-film transistor (TFT) inverters with top and bottom gate structures with $Al_2O_3$ dielectrics grown by atomic layer deposition (ALD). Since the top gate ZnO-based TFT showed somewhat lower field effect mobility than that of the bottom gate device, our ZnO-based TFT inverters were designed with identical dimensions for both channels. This TFT inverter device demonstrated an high voltage gain at a low supply voltage of 5 V and clear dynamic behavior.

• Journal of the Semiconductor & Display Technology
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• v.9 no.3
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• pp.75-78
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• 2010

In this study we investigated the electrical properties of ZnO-based MOS capacitor with $HfO_2$ as the gate dielectric. MIM capacitor, which uses either $HfO_2$ or $Al_2O_3$ as the dielectric layer, is also studied to understand the dependency of the dielectrics on the preparation conditions. It was found that thinner $HfO_2$ films yield better electrical properties, namely lower leakage current and higher breakdown electric field. These properties were observed to deteriorate when subsequently annealed. Capacitance in the depletion region of MOS capacitor was found to increase with UV ozone treatment time up to 60min. However, when the treatment time was extended to 120min, the trend is reversed. The 'threshold voltage' was also observed to positively shift with UV ozone treatment time up to 60min. The shift apparently saturated for longer treatment.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.6
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• pp.64-69
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• 1984

We found that the maximum efficiency of Al-MIS (p-Si) solar ceil was shown at 80$\AA$ thickness of Al-film which was deposited with slower velocity than 0.6$\AA$/sec. It was coated with ZnS and SiO for Anti-Reflecting. In single coating, ZnS and SiO film had maximum Isc at 570 and 690 A thickness, respectively. We confirmed that these results agreed well with the quarter coating condition; n1d1=λ/4. In double coating, we held the one layer with its optimum thickness in single coating and controlled the other layer. The maximum value of Isc in this case was almost the same with it in single coating but was maintained its value in so wide range of thickness. Keeping the relation; n1d1=n2d2 as another way, we made the total thickness of film thinner to 70-90% of the sum of each optimum thickness in single coating. In this case Isc was higher value than 20% of it in any other previous case and was retained so wide range of thickness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.55-56
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• 2005

The properties of phosphorus doped ZnO thin films deposited on (001) sapphire substrates by pulsed laser deposition (PLD) were investigated depending on various deposition conditions. The phosphorus (P) doped ZnO target was composed of ZnO + x wt% Al (x=1, 3, 5). The structural, electrical and optical properties of the ZnO thin films were measured by X-ray diffraction (XRD), Hall measurements and photoluminescence (PL). As the deposition temperature optimized, the electrical properties of the phosphorus doped ZnO (ZnO:P) layer showed a electron concentration of $7.76\times10^{16}/cm^3$, a mobility of 10.225 $cm^2/Vs$, a resistivity of 7.932 $\Omega$cm. It was observed the electrical property of the film was changed by dopant activation effect as target variations and deposition conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.68-69
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• 2007

We have prepared p-type ZnO:Al films in pure oxygen ambient on n-type Si (100) and homo buffer layers by RF magnetron sputtering system. Hall effect measurement shows that the film annealed at $600^{\circ}C$ possesses p-type conductivity and the film annealed $800^{\circ}C$ does not. PL spectra show different properties of p- and n-type ZnO film. The corresponding peaks of PL spectra of p- and n-type show at about same positions. The intensities of high photon energy of n-type film on buffer shows decreasing tendency.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.264-264
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• 2016

최근에 charge trap flash (CTF) 기술은 절연막에 전하를 트랩과 디트랩 시킬 때 인접한 셀 간의 간섭현상을 최소화하여 오동작을 줄일 수 있으며 낸드 플래시 메모리 소자에 적용되고 있다. 낸드 플래시 메모리는 고집적화, 대용량화와 비휘발성 등의 장점으로 인해 핸드폰, USB, MP3와 컴퓨터 등에 이용되고 있다. 기존의 실리콘 기반의 플래시 메모리 소자는 좁은 밴드갭으로 인해 투명하지 않고 고온에서의 공정이 요구되는 문제점이 있다. 따라서, 이러한 문제점을 개선하기 위해 실리콘의 대체 물질로 산화물 반도체 기반의 플래시 메모리 소자들이 연구되고 있다. 산화물 반도체 기반의 플래시 메모리 소자는 넓은 밴드갭으로 인한 투명성을 가지고 있으며 저온에서 공정이 가능하여 투명하고 유연한 기판에 적용이 가능하다. 다양한 산화물 반도체 중에서 비정질 In-Ga-Zn-O (a-IGZO)는 비정질임에도 불구하고 우수한 전기적인 특성과 화학적 안정성을 갖기 때문에 많은 관심을 받고 있다. 플래시 메모리의 고집적화가 요구되면서 절연막에 high-k 물질을 atomic layer deposition (ALD) 방법으로 적용하고 있다. ALD 방법을 이용하면 우수한 계면 흡착력과 균일도를 가지는 박막을 정확한 두께로 형성할 수 있는 장점이 있다. 또한, high-k 물질을 절연막에 적용하면 높은 유전율로 인해 equivalent oxide thickness (EOT)를 줄일 수 있다. 특히, HfOx와 AlOx가 각각 trap layer와 blocking layer로 적용되면 program/erase 동작 속도를 증가시킬 수 있으며 넓은 밴드갭으로 인해 전하손실을 크게 줄일 수 있다. 따라서 본 연구에서는 ALD 방법으로 AlOx와 HfOx를 게이트 절연막으로 적용한 a-IGZO 기반의 thin-film transistor (TFT) 플래시 메모리 소자를 제작하여 메모리 특성을 평가하였다. 제작 방법으로는, p-Si 기판 위에 열성장을 통한 100 nm 두께의 SiO2를 형성한 뒤, 채널 형성을 위해 RF sputter를 이용하여 70 nm 두께의 a-IGZO를 증착하였다. 이후에 소스와 드레인 전극에는 150 nm 두께의 In-Sn-O (ITO)를 RF sputter를 이용하여 증착하였고, ALD 방법을 이용하여 tunnel layer에 AlOx 5 nm, trap layer에 HfOx 20 nm, blocking layer에 AlOx 30 nm를 증착하였다. 최종적으로, 상부 게이트 전극을 형성하기 위해 electron beam evaporator를 이용하여 platinum (Pt) 150 nm를 증착하였고, 계면 결함을 최소화하기 위해 퍼니스에서 질소 가스 분위기, $400^{\circ}C$, 30 분의 조건으로 열처리를 했다. 측정 결과, 103 번의 program/erase를 반복한 endurance와 104 초 동안의 retention 측정으로부터 큰 열화 없이 메모리 특성이 유지되는 것을 확인하였다. 결과적으로, high-k 물질과 산화물 반도체는 고성능과 고집적화가 요구되는 향후 플래시 메모리의 핵심적인 물질이 될 것으로 기대된다.