• Title/Summary/Keyword: AlN layer

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Characteristics of AlN thin films for SAW filters based on substrates (기판의 종류에 따른 SAW 필터용 AlN 박막의 특성)

  • Ko, Bong-Chul;Nam, Chang-Woo
    • Journal of Sensor Science and Technology
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    • v.16 no.3
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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.

Analysis on Bowing and Formation of Al Doped P+ Layer by Changes of Thickness of N-type Wafer and Amount of Al Paste (N타입 결정질 실리콘 웨이퍼 두께 및 알루미늄 페이스트 도포량 변화에 따른 Bowing 및 Al doped p+ layer 형성 분석)

  • Park, Tae Jun;Byun, Jong Min;Kim, Young Do
    • Korean Journal of Materials Research
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    • v.25 no.1
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    • pp.16-20
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    • 2015
  • In this study, in order to improve the efficiency of n-type monocrystalline solar cells with an Alu-cell structure, we investigate the effect of the amount of Al paste in thin n-type monocrystalline wafers with thicknesses of $120{\mu}m$, $130{\mu}m$, $140{\mu}m$. Formation of the Al doped $p^+$ layer and wafer bowing occurred from the formation process of the Al back electrode was analyzed. Changing the amount of Al paste increased the thickness of the Al doped $p^+$ layer, and sheet resistivity decreased; however, wafer bowing increased due to the thermal expansion coefficient between the Al paste and the c-Si wafer. With the application of $5.34mg/cm^2$ of Al paste, wafer bowing in a thickness of $140{\mu}m$ reached a maximum of 2.9 mm and wafer bowing in a thickness of $120{\mu}m$ reached a maximum of 4 mm. The study's results suggest that when considering uniformity and thickness of an Al doped $p^+$ layer, sheet resistivity, and wafer bowing, the appropriate amount of Al paste for formation of the Al back electrode is $4.72mg/cm^2$ in a wafer with a thickness of $120{\mu}m$.

Characterization of TiAlN Coated Layer with Heat Treatment Prepared by R.F Magnetron Sputtering (R.F magnetron sputtering법으로 제조된 TiAlN 코팅 층의 열처리 특성)

  • Song, Dong Hwan;Yang, Gwon Seung;Lee, Jong Kook
    • Journal of the Korean Society for Heat Treatment
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    • v.19 no.4
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    • pp.225-229
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    • 2006
  • TiAlN coatings are available in various industry fields as a wear resistant coating for high-speed machining, due to its high hardness, excellent oxidation and corrosion resistance. The corrosion resistance of TiAlN multilayer coatings is better than that of single TiN coatings. Most of TiAlN coated layers were formed by heat treatment of coating layers with a non-stoichiometric $Ti_xAl_{1-x}N$. In this study, TiAlN coated layer was prepared by R.F magnetron sputtering and investigated the thermal behavior for heat treatment at various temperature in tube furnace. The formation of large particles with porous microstructure and phase change from HCP to FCC were observed on coated layer during heat treatment over $850^{\circ}C$ and it reduced the corrosion resistance of coated TiAlN layers.

The Effect of Quantum Well Structure on the Characteristics of GaN-based Light-Emitting Diode (양자 우물 구조가 GaN 기반 LED 특성에 미치는 영향)

  • Lee, Jae-Hyun;Yeom, Keesoo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2012.10a
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    • pp.251-254
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    • 2012
  • In this paper, the output characteristics of GaN-based LED considering quantum well structure are analyzed. The basic structure of the LED consists of active region of GaN barrier and InGaN quantum well between AlGaN EBL(Electron Blocking Layer) and AlGaN HBL(Hole Blocking Layer) on GaN buffer layer. The output power, internal quantum efficiency characteristics of LED active region considering thickness of quantum well, number of quantum well and doping of barrier are analyzed using ISE-TCAD.

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SAW characteristics of AlN films sputtered on SiC buffer layer for harsh environment applications (SiC 버퍼충위 스퍼터링법으로 증착된 극한 환경용 AlN박막의 SAW 특성)

  • Hoang, Si-Hong;Chung, Gwiy-Sang
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.273-273
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    • 2008
  • This paper describes the frequency response of two-port surface acoustic wave (SAW) resonator made of 002-polycrystalline aluminum nitride (AlN) thin film on 111-poly 3C-SiC buffer layer. In there, Polycrystalline AlN thin films were deposited on polycrystalline 3C-SiC buffer layer by pulsed reactive magnetron sputtering system, the polycrystalline 3C-SiC was grown on $SiO_2$/Si sample by CVD. The obtained results such as the temperature coefficient of frequency (TCF) of the device is about from 15.9 to 18.5 ppm/$^{\circ}C$, the change in resonance frequency is approximately linear (30-$150^{\circ}C$), which resonance frequency of AlN/3C-SiC structure has high temperature stability. The characteristics of AlN thin films grown on 3C-SiC buffer layer are also evaluated by using the XRD, and AFM images.

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Oxidation of CrAlMgSiN thin films between 600 and 900℃ in air (CrAlMgSiN 박막의 600-900℃에서의 대기중 산화)

  • Won, Seong-Bin;Xu, Chunyu;Hwang, Yeon-Sang;Lee, Dong-Bok
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2013.05a
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    • pp.112-113
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    • 2013
  • Thin CrAlMgSiN films, whose composition were 30.6Cr-11.1Al-7.3Mg-1.2Si-49.8N (at.%), were deposited on steel substrates in a cathodic arc plasma deposition system. They consisted of alternating crystalline Cr-N and AlMgSiN nanolayers. After oxidation at $800^{\circ}C$ for 200 h in air, a thin oxide layer formed by outward diffusion of Cr, Mg, Al, Fe, and N, and inward diffusion of O ions. Silicon ions were relatively immobile at $800^{\circ}C$. After oxidation at $900^{\circ}C$ for 10 h in air, a thin $Cr_2O_3$ layer containing dissolved ions of Al, Mg, Si, and Fe formed. Silicon ions became mobile at $900^{\circ}C$. After oxidation at $900^{\circ}C$ for 50 h in air, a thin $SiO_2-rich$ layer formed underneath the thin $Cr_2O_3$ layer. The film displayed good oxidation resistance. The main factor that decreased the oxidation resistance of the film was the outward diffusion and subsequent oxidation of Fe at the sample surface, particularly along the coated sample edge.

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Raman Scattering Characteristics of Polycrystalline 3C-SiC Thin Films deposited on AlN Buffer Layer (AlN 버퍼층위에 증착된 다결정 3C-SiC 박막의 라만 산란 특성)

  • Chung, Gwiy-Sang;Kim, Kang-San
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.21 no.6
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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.

Design of Normally-Off AlGaN Heterojunction Field Effect Transistor Based on Polarization Engineering (분극 엔지니어링을 통한 상시불통형 질화알루미늄갈륨 이종접합 전계효과 트랜지스터 설계)

  • Cha, Ho-Young;Sung, Hyuk-Kee
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.16 no.12
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    • pp.2741-2746
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    • 2012
  • In this study, we propose a novel structure based on AlGaN substrate or buffer layer to implement a normally-off mode transistor that was difficult to be realized by conventional AlGaN/GaN heterojunction structures. The channel under the gate can be selectively depleted by growing an upper AlGaN barrier with a higher Al mole fraction and a top GaN charge elimination layer on AlGaN substrate or buffer layer. The proposed AlGaN heterojunction field effect transistor can achieve a threshold voltage of > 2 V, which is generally required in power device specification.

High temperature air-oxidation of CrAlSiN thin films (CrAlSiN 박막의 대기중 고온산화)

  • Hwang, Yeon-Sang;Won, Seong-Bin;Chunyu, Xu;Kim, Seon-Gyu;Lee, Dong-Bok
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2013.05a
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    • pp.53-54
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    • 2013
  • Nano-multilayered CrAlSiN films consisting of crystalline CrN nanolayers and amorphous AlSiN nanolayers were deposited by cathodic arc plasma deposition. Their oxidation characteristics were studied between 600 and $1000^{\circ}C$ for up to 70 h in air. During their oxidation, the amorphous AlSiN nanolayers crystallized. The formed oxides consisted primarily of $Cr_2O_3$, ${\alpha}-Al_2O_3$, $SiO_2$. The outer $Al_2O_3$ layer formed by outward diffusion of Al ions. Simultaneously, an inner ($Al_2O_3$, $Cr_2O_3$)-mixed layer formed by the inward diffusion of oxygen ions. $SiO_2$ was present mainly in the lower part of the oxide layer due to its immobility. The CrAlSiN films displayed good oxidation resistance, owing to the formation of oxide crystallites of $Cr_2O_3$, ${\alpha}-Al_2O_3$, and amorphous $SiO_2$.

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Effect of $Al_2O_3$ pre-layers formed using protective Si-oxide layer on the growth of ultra thin ${\gamma}-Al_2O_3$ epitaxial layer (보호용 실리콘 산화막을 이용하여 제조된 $Al_2O_3$ 예비층이 초박막 ${\gamma}-Al_2O_3$ 에피텍시의 성장에 미치는 영향)

  • Jung, Young-Chul;Jun, Bon-Keun;Ishida, Makoto
    • Journal of Sensor Science and Technology
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    • v.9 no.5
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    • pp.389-395
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    • 2000
  • In this paper, we propose the formation of an $Al_2O_3$ pre-layer using a protective Si-oxide layer and Al layer. Deposition of a thin film layer of aluminum onto a Si surface covered with a thin Si-oxide layer and annealing at $800^{\circ}C$ led to the growth of epitaxial $Al_2O_3$ layer on Si(111). And ${\gamma}-Al_2O_3$ layer was grown on the $Al_2O_3$ per-layer. Etching of the Si substrate by $N_2O$ gas could be avoided in the initial growth stage by the $Al_2O_3$ pre-layer. It was confirmed that the $Al_2O_3$ pre-layer was effective in improving the surface morphology of the very thin ${\gamma}-Al_2O_3$ films.

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