• 한국전기전자재료학회논문지
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• 제17권2호
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• pp.178-183
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• 2004

PBT thin film was known to be a representative for the FeRAM devices because of its good ferroelectric proporties and the ease in fabricating the thin film. However, there have been several problems such as polarization fatigue and leakage current in memory devices with a PZT thin film. In this study, Sm-dolled PZT thin films were fabricated by the so1-gel method, and their ferroelectric and dielectric proportrics were compared as a function of Sm content. We investigated the effect of the Sm dopant on structural and electrical properties of PZT film. Sm-doped PZT thin films on the Pt/Ti/SiO$_2$/Si substrates have been prepared by a sol-gel method. The remanent polarization and coercive field decreased with increasing the concentration of Sm. The dielectric constant and dielectric loss decreased with Increasing Sm content. Sm-doped PZT thin films showed improved fatigue characteristics compared to the undoped PZT thin film.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.953-956
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• 2003

Hexagonal GaN (h-GaN) films have been grown on Si(111) substrates by metal organic chemical vapor deposition using the azidodiethylgallium methylamine adduct, Et₂Ga(N₃)·NH₂Me, as a new single precursor. Deposition was carried out in the substrate temperature range 385-650 °C. The GaN films obtained were stoichiometric and did not contain any appreciable amounts of carbon impurities. It was also found that the GaN films deposited on Si(111) had the [0001] preferred orientation. The photoluminescence spectrum of a GaN film showed a band edge emission peak characteristic of h-GaN at 378 nm.

• Current Photovoltaic Research
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• 제1권1호
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• pp.27-32
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• 2013

We investigated the growth mechanism of amorphous-phase Si thin films in order to improve the film characteristics and circumvent photo-degradation effects by implementation of hot-wire chemical vapor deposition. Amorphous silicon thin films grown in a silane/hydrogen mixture can be decomposed by a resistive heat filament. The structural properties were observed by Raman spectroscopy, FTIR, SEM, and TEM. The electrical properties of the films were measured by photo-conductivity, dark-conductivity, and photo-sensitivity. The contents of Si-H and $Si-H_n$ bonds were measured to be 19.79 and 9.96% respectively, at a hydrogen flow rate of 5.5 sccm, respectively. The thin film has photo-sensitivity of $2.2{\times}10^5$ without a crystalline volume fraction. The catalyst behavior of the hot-wire to decompose the chemical precursors by an electron tunneling effect depends strongly on the hydrogen mixture rate and an amorphous Si thin film is formed from atomic relaxation.

• 센서학회지
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• 제6권6호
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• pp.483-490
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• 1997

Thin film Si has been used in sensors, radiation detectors, and solar cells. The carrier mobility of thin film Si influences the device behavior through its frequency response or time response. Since poly-Si shows the higher mobility value, a-Si:H films on Mo substrate were subjected to various crystallization treatments. Consequently, we need to find an appropriate method in mobility measurement before and after the anneal treatment. This paper investigates the carrier mobility improvement with anneal treatments and summarizes the mobility measurement methods of the a-Si:H and poly-Si film. Various techniques were investigated for the mobility determination such as Hall mobility, HS, TOF, SCLC, TFT, and TCO method. We learned that TFT and TCO method are suitable for the mobility determination of a-Si:H and poly-Si film. The measured mobility was improved by $2{\sim}3$ orders after high temperature anneal above $700^{\circ}C$ and grain boundary passivation using an RF plasma rehydrogenation.

• 한국재료학회지
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• 제21권6호
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• pp.341-346
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• 2011

In this study, we inserted a Zn buffer layer into a AZO/p-type a-si:H layer interface in order to lower the contact resistance of the interface. For the Zn layer, the deposition was conducted at 5 nm, 7 nm and 10 nm using the rf-magnetron sputtering method. The results were compared to that of the AZO film to discuss the possibility of the Zn layer being used as a transparent conductive oxide thin film for application in the silicon heterojunction solar cell. We used the rf-magnetron sputtering method to fabricate Al 2 wt.% of Al-doped ZnO (AZO) film as a transparent conductive oxide (TCO). We analyzed the electro-optical properties of the ZnO as well as the interface properties of the AZO/p-type a-Si:H layer. After inserting a buffer layer into the AZO/p-type a-Si:H layers to enhance the interface properties, we measured the contact resistance of the layers using a CTLM (circular transmission line model) pattern, the depth profile of the layers using AES (auger electron spectroscopy), and the changes in the properties of the AZO thin film through heat treatment. We investigated the effects of the interface properties of the AZO/p-type a-Si:H layer on the characteristics of silicon heterojunction solar cells and the way to improve the interface properties. When depositing AZO thin film on a-Si layer, oxygen atoms are diffused from the AZO thin film towards the a-Si layer. Thus, the characteristics of the solar cells deteriorate due to the created oxide film. While a diffusion of Zn occurs toward the a-Si in the case of AZO used as TCO, the diffusion of In occurs toward a-Si in the case of ITO used as TCO.

• 한국전기전자재료학회논문지
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• 제17권6호
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• pp.580-585
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• 2004

Silicon dioxide (SiO$_2$) is widely used as a gate dielectric material for thin film transistors (TFT) and semiconductor devices. In this paper, SiO$_2$ films were grown by APCVD(Atmospheric Pressure chemical vapor deposition) at the high temperature. Experimental investigations were carried out as a function of $O_2$ gas flow ratios from 0 to 200 1pm. This article presents the SiO$_2$ gate dielectric studies in terms of deposition rate, refrative index, FT-IR, C-V for the gate dielectric layer of thin film transistor applications. We also study defect passivation technique for improvement interface or surface properties in thin films. Our passivation technique is Forming Gas Annealing treatment. FGA acts passivation of interface and surface impurity or defects in SiO$_2$ film. We used RTP system for FGA and gained results that reduced surface fixed charge and trap density of midgap value.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.246-248
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• 1994

The Electrical properties of thin $SiO_2$ film by rapid thermal processing have been investigated and this film has been compared with thermal $SiO_2$ film by furnace. The RTO(rapid thermal oxide) film annealed in Ar ambient represent more superior properties than thermal $SiO_2$ film by furnace at breakdown field and leakage current. The RTO(rapid thermal oxide) film annealed in $NH_3$ ambient represent more inferior properties than thermal $SiO_2$ film by furnace at electrical properties, but the capacitance was improved 15-25% than the conventional oxide film.

• 한국표면공학회지
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• 제47권3호
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• pp.99-103
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• 2014

The encapsulation method of flexible organic light emitting devices (OLEDs) was investigated for the structure of ITO / 2-TNATA / NPB / $Alq_3$ : Rubrene (1 vol.%) / $Alq_3$ / LiF / Al / $Alq_3$ / LiF / Al (OLED #1), on which $SiN_x$ thin film was deposited and metal film was attached to protect the damage of OLED from oxygen and moisture. The $SiN_x$ thin film was deposited by plasma enhanced chemical vapor deposition (PECVD) method using $SiH_4$ of 20 sccm and $N_2$ of 15~35 sccm as reactor gases. The optimum $SiN_x$ deposition condition was found to be 20 sccm $SiH_4$ and 20 sccm $N_2$ from the Ca test of the fabricated $SiN_x$ thin film. The life time of OLED #1, OLED #1 / $SiN_x$ 200 nm, OLED #1 / $SiN_x$ 400 nm and OLED #1 / $SiN_x$ 400 nm / metal film was 7, 12, 25, and 45 hours, respectively. In conclusion, it has been shown that the lifetime of OLEDs can be improved more than 6 times by $SiN_x$ film and a metal film encapsulation.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권3호
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• pp.111-116
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• 2004

The Ni/SiC Schottky diode was fabricated with the $\alpha$-SiC thin film grown by the ICP-CVD method on a (111) Si wafer. $\alpha$-SiC film has been grown on a carbonized Si layer in which the Si surface was chemically converted to a very thin SiC layer achieved using an ICP-CVD method at $700^{\circ}C$. To reduce defects between the Si and $\alpha$-SiC, the surface of the Si wafer was slightly carbonized. The film characteristics of $\alpha$-SiC were investigated by employing TEM (Transmission Electron Microscopy) and FT-IR (Fourier Transform Infrared Spectroscopy). Sputterd Ni thin film was used as the anode metal. The boundary status of the Ni/SiC contact was investigated by AES (Auger Electron Spectroscopy) as a function of the annealing temperature. It is shown that the ohmic contact could be acquired beyond a 100$0^{\circ}C$ annealing temperature. The forward voltage drop at 100A/cm was I.0V. The breakdown voltage of the Ni/$\alpha$-SiC Schottky diode was 545 V, which is five times larger than the ideal breakdown voltage of the silicon device. As well, the dependence of barrier height on temperature was observed. The barrier height from C- V characteristics was higher than those from I-V.

• 한국전기전자재료학회논문지
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• 제19권8호
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• pp.732-736
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• 2006

This paper describes the physical characterizations of polycrystalline 3C-SiC thin films heteroepitaxially grown on Si wafers with thermal oxide, In this work, the 3C-SiC film was deposited by LPCVD (low pressure chemical vapor deposition) method using single precursor 1, 3-disilabutane $(DSB:\;H_3Si-CH_2-SiH_2-CH_3)\;at\;850^{\circ}C$. The crystallinity of the 3C-SiC thin film was analyzed by XPS (X-ray photoelectron spectroscopy), XRD (X-ray diffraction) and FT-IR (fourier transform-infrared spectometers), respectively. The surface morphology was also observed by AFM (atomic force microscopy) and voids or dislocations between SiC and $SiO_2$ were measured by SEM (scanning electron microscope). Finally, residual strain was investigated by Raman scattering and a peak of the energy level was less than other type SiC films, From these results, the grown poly 3C-SiC thin film is very good crystalline quality, surface like mirror, and low defect and strain. Therefore, the polycrystalline 3C-SiC is suitable for harsh environment MEMS (Micro-Electro-Mechanical-Systems) applications.