• 한국응용과학기술학회지
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• 제20권2호
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• pp.173-176
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• 2003

We have seen the effects of buffer layer in organic light-emitting diodes using poly(N-vinylcarbazole)(PVK). Polymer PVK buffer layer was made using static spin-casting method. Two device structures were made; one is ITO/TPD/Alq3/Al as a reference and the other is ITO/PVK/TPD/Alq3/Al to see the effects of buffer layer in organic light-emitting diodes. Current-voltage characteristics, luminance-voltage characteristics and luminous efficiency were measured with a variation of spin-casting speeds. We have obtained an improvement of luminous efficiency by a factor of two and half when the PVK buffer layer is used.

• 한국전기전자재료학회논문지
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• 제21권6호
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• pp.493-498
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• 2008

This Paper describes the Raman scattering characteristics of polycrystalline (Poly) 3C-SiC thin films, in which they were deposited on AlN buffer layer by APCVD using hexamethyldisilane (MHDS) and carrier gases (Ar+$H_2$). When the Raman spectra of SiC films deposited on the AlN layer of before and after annealing were worked according to growth temperature, D and G bands of graphite were measured. It can be explained that poly 3C-SiC films admixe with nanoparticle graphite and its C/Si rate is higher than ($C/Si\;{\approx}\;3$) that of the conventional SiC, which has no D and G bands related to graphite. From the Raman shifts of 3C-SiC films deposited at $1180^{\circ}C$ on the AlN layer of after annealing, the biaxial stress of poly 3C-SiC films was obtained as 896 MPa.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.82-85
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• 2002

In recent years, the tantalum nitride(TaN) thin-film has been developed for the electronic resistor and capacitor. In this papers, this study presents the surface profile and sheet-resistance property relationship of reactive-sputtered TaN thin film resistor processed by buffer of Ti and Cr on alumina substrate. The TCR properties of the TaN films were discussed in terms of reactive gas ratio, ratio of nitrogen, crystallization and thin films surface morphology due to annealing temperature. It is clear that the TaN thin-films resistor electrical properties are low TCR related with it's buffer layer condition. Ti buffer layer thin film resistor having a good thermal stability and lower TCR properties then Cr buffer expected for the application to the dielectric material of passive component.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.93-93
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• 2008

This paper presents the Raman scattering characteristics of poly (polycrystalline) 3C-SiC thin films deposited on AlN buffer layer by atmospheric pressure chemical vapor deposition (APCVD) using hexamethyldisilane (MHDS) and carrier gases (Ar + $H_2$).The Raman spectra of SiC films deposited on AlN layer of before and after annealings were investigated according to the growth temperature of 3C-SiC. Two strong Raman peaks, which mean that poly 3C-SiC admixed with nanoparticle graphite, were measured in them. The biaxial stress of poly 3C-SiC/AlN was calculated as 896 MPa from the Raman shifts of 3C-SiC deposited at $1180^{\circ}C$ on AlN of after annealing.

• 센서학회지
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• 제16권3호
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• pp.240-245
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• 2007

AlN thin film for SAW filter application was deposited on (100) silicon, sapphire, $Si_{3}N_{4}$/Si, and $Al_{2}O_{3}$/Si substrates by reactive magnetron sputtering method, respectively. The structural characteristics were dependent on the structure of substrates. Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Atomic Force Microscope (AFM) have been used to analyze structural properties and preferred orientation of AlN thin films. Preferred orientation and SAW characteristic of AlN were improved by insertion of $Al_{2}O_{3}$ buffer layer. Insertion loss of SAW devices using AlN/Si and AlN/$Al_{2}O_{3}$/Si were about 33.27 dB and 30.20 dB, respectively.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.333-334
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• 2007

This paper describes the characteristics of poly (polycrystalline) 3C-SiC grown on SiOz and AlN substrates, respectively. The crystalline quality of poly 3C-SiC was improved from resulting in decrease of FWHM (full width half maximum) of XRD by increasing the growth temperature. The minimum growth temperature of poly 3C-SiC was $1100^{\circ}C$. The surface chemical composition and the electron mobility of poly 3C-SiC grown on each substrate were investigated by XPS and Hall Effect, respectively. The chemical compositions of surface of poly 3C-SiC films grown on $SiO_2$ and AlN were not different. However, their electron mobilities were $7.65\;cm^2/V.s$ and $14.8\;cm^2/V.s$, respectively. Therefore, since the electron mobility of poly 3C-SiC films grown on AlN buffer layer was two times higher than that of 3C-SiC/$SiO_2$, a AlN film is a suitable material, as buffer layer, for the growth of poly 3C-SiC thin films with excellent properties for M/NEMS applications.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.132-132
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• 2011

The sheet resistance (Rs) of undoped GaN films on AlN/c-plane sapphire substrate was investigated in which the AlN films were grown by R. F. magetron sputtering method. The Rs was strongly dependent on the AlN layer thickness and semi-insulating behavior was observed. To clarify the effect of crystalline property on Rs, the crystal structure of the GaN films has been studied using x-ray scattering and transmission electron microscopy. A compressive strain was introduced by the presence of AlN nucleation layer (NL) and was gradually relaxed as increasing AlN NL thickness. This relaxation produced more threading dislocations (TD) of edge-type. Moreover, the surface morphology of the GaN film was changed at thicker AlN layer condition, which was originated by the crossover from planar to island grains of AlN. Thus, rough surface might produce more dislocations. The edge and mixed dislocations propagating from the interface between the GaN film and the AlN buffer layer affected the electric resistance of GaN film.

• 한국진공학회지
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• 제14권4호
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• pp.201-206
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• 2005

본 연구에서는 HVPE (Hydride Vapor Phase Epitaxy) 방법으로 Si 위에 GaN/AIN/Al/Si 구조를 제작하고, AlN 버퍼층의 두께에 따른 광학적 특성을 조사함으로써 효과적인 eaN 성장을 위한HVPE에서의 공정 방법을 개선하고자 하였다. 이를 위해 Al을 증착한 Si 기판과 그렇지 않은 경우를 PL측정을 통해 그 효과를 관찰하였고, $5{\AA}$ 두께의 Al 대해 AlN 버퍼층의 두께를 변화시켜가면서 GaN를 성장시켜 그 특성을 조사하였다. Al을 증착한 경우가 증착하지 않은 경우에 비해 광학적 특성이 우수한 것으로 나타났으며, AlN의 두께 변화에 대해서는 양질의 GaN를 얻기 위한 최적의 두께는 약 $260{\AA}$ 인 것으로 나타났다. 이 경우 SEM을 이용한 표면사진에서 GaN의 초기성장이 hexagonal형태로 성장되고 있음을 관찰할 수 있었다. 또한 XRD의 회절 패턴은 GaN가 {0001} 방향으로 우선 배향성을 가지고 성장되고 있음을 보여주고 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.326-329
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• 2002

In this paper, we investigated a feasibility of cerium oxide(CeO$_2$) films as a buffer layer of MFIS(metal ferroelectric insulator semiconductor) type capacitor. CeO$_2$ layer were Prepared by two step process of a low temperature film growth and subsequent RTA (rapid thermal annealing) treatment. By app1ying an ultra thin Ce metal seed layer and N$_2$ Plasma treatment, dielectric and interface properties were improved. It means that unwanted SiO$_2$ layer generation was successfully suppressed at the interface between He buffer layer and Si substrate. The lowest lattice mismatch of CeO$_2$ film was as low as 1.76% and average surface roughness was less than 0.7 m. The Al/CeO$_2$/Si structure shows breakdown electric field of 1.2 MV/cm, dielectric constant of more than 15.1 and interface state densities as low as 1.84${\times}$10$\^$11/ cm$\^$-1/eV$\^$-1/. After N$_2$ plasma treatment, the leakage current was reduced with about 2-order.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.346-347
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• 2007

Aluminum nitride (AlN) thin films were deposited on Polycrystalline (poly) 3C-SiC buffer layers using pulsed reactive magnetron sputtering. Characteristics of AlN films were investigated experimentally by means of FE-SEM, X-ray diffraction, and FT-IR, respectively. As a result, highly (002) oriented AlN thin films with almost free residual stress were achieved using 3C-SiC buffer layers. Therefore, AlN thin films grown on 3C-SiC buffer layers can be used for various piezoelectric fields and M/NEMS applications.