• 제목/요약/키워드: pulsed laser depostion

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펄스 레이저 증착법으로 성장된 투명 TFTs 채널층을 위한 ZnO 박막 분석 (Characterization of ZnO Thin Films Grown by Pulsed Laser Deposition for Channel Layer of Transparent TFTs)

  • 이원용;김지홍;노지형;조대형;문병무;구상모
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.77-78
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    • 2008
  • ZnO thin films were deposited on glass substrates by pulsed laser deposition (PLD) at various oxygen pressures. We observed structural, electrical and optical properties of ZnO films. Structural properties were analysed by XRD and FE-SEM. Electrical properties for applications of transparent thin film transistors (TTFTs) were measured by hall measurement using van der pauw methods at room temperature. In order to apply in transparent devices, we measured transmittance, and optical bandgap energy was calculated by Tauc's equation. The results showed that ZnO films deposited at 200mTorr oxygen pressure were applicable to channel layers of transparent TFTs. It had high hall mobilities ($52.92cm^2$/V-s) and suitable transmittance at visible wavelength region (above 80%).

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Pulsed laser depostion (PLD)법으로 증착된 $BaTiO_3/SrTiO_3$ 산화물 초격자의 성장 및 유전특성 (Growth and dielectric Properties or $BaTiO_3/SrTiO_3$ oxide artificial superlattice deposited by pulsed laser deposition (PLD))

  • 김주호;김이준;정동근;김용성;이재찬
    • 한국진공학회지
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    • 제11권3호
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    • pp.166-170
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    • 2002
  • $BaTiO_3$(BTO)/$SrTiO_3$(STO) 산화물 인공 초격자가 MgO(100) 단결정 기판위에 Pulsed laser deposition(PLD)법으로 증착되었다. 다층구조에서 BTO/STO 층의 적층 주기는 $BTO_{1\;unit\; cell}/STO_{1\;unit\; cell}$에서 $BTO_{125\;unit\; cell}/STO_{125 \;unit \;cell}$ 두께로 변화시켰고 초격자 전체 두께는 100 m으로 고정시켰다. X-ray 회절 결과는 다양한 주기의 BTO/STO 산화물 박막에서 초격자의 특성을 보였고 투과형 전자 현미경을 통해서 BTO와 STO의 두 층간의 계면에서 상호확산이 일어나지 않고 초격자가 잘 성장된 것을 확인하였다. 초격자의 유전율은 임계 두께 내에서 적층주기가 감소함에 따라 증가하였다. 이러한 초격자의 유전율은 낮은 주기 즉 $BTO_{2\;unit\; cell}/STO_{2\;unit\; cell}$ 주기에서 1230으로 높게 나왔으며 이러한 원인은 격자 변형(c/a ratio)에 기여된 것으로 분석되었다.

(Bi,Nd)(Fe,Ti)O3 세라믹스와 박막의 상형성 거동 (Phase Evolution Behavior of (Bi,Nd)(Fe,Ti)O3 Ceramics and Thin Films)

  • 김경만;이희영
    • 한국전기전자재료학회논문지
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    • 제23권12호
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    • pp.949-955
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    • 2010
  • Nd and Ti co-doped bismuth ferrite $(Bi_{1-x}Nd_x)(Fe_{1-y}Ti_y)O_3$ (x, y = 0, 0.05, 0.1, 0.2) ceramics and thin films were synthesized through the conventional mixed-oxide process and pulsed laser deposition (PLD), respectively. Nd and Ti co-doping effect was examined with emphasis on how these impurities affect phase formation behavior as there could be the improvement in leakage current problems often associated with multiferroic $BiFeO_3$ (BFO) thin films. The lattice constants of BFO ceramics decreased with Nd doping concentration up to 10mol%, while they further decreased with Nd and Ti co-doping to about 20%. BFO thin films obtained by the PLD process revealed random polycrystalline structure. Similar to bulk BFO ceramic, Nd and Ti co-doping effectively suppressed the formation of unwanted secondary phase and thus stabilized the perovskite phase in BFO thin films.