• 제목/요약/키워드: Crystallographic properties

검색결과 389건 처리시간 0.02초

저압 MOCVD로 CBr4 가스를 사용하여 탄소 도핑된 GaAs 에피층의 결정학적 방향에 따른 전기적 성질의 의존성 (Crystallographic Orientation Dependence Of Electrical Properties of Carbon-doped GaAs Grown by Low Pressure Metalorganic Chemical Vapor Deposition Using CBr4)

  • 손창식
    • 한국전기전자재료학회논문지
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    • 제15권3호
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    • pp.214-219
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    • 2002
  • In order to elucidate the crystallographic orientation dependence of electrical properties of carbon (C)-doped GaAs epilayers, C incorporation into GaAs epilayers on high-index GaAs substrates with various crystallographic orientations from (100) to (111)A has been performed by a low pressure metalorganic chemical vapor deposition using C tetrabromide ($CBt_4$) as a C source. The hole concentration of C-doped GaAs epilayers rapidly decreases with a hump at (311)A with increasing the offset angle. Although the growth temperature and the V/III ratio are varied, the crystallographic orientation dependence of hole concentration show a same trend. The above behaviors indicate that the bonding strength of As sites on a glowing surface plays an important role in the C incorporation into the high-index GaAs substrates.

The Symmetry of Aurivillius Ceramics

  • Fuentes, Luis;Fuentes, Maria E.;Camacho, Hector
    • 한국결정학회지
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    • 제12권4호
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    • pp.227-232
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    • 2001
  • Structure-physical properties relationships for Aurivillius ceramics are discussed, with empha-sis in symmetry considerations. Single-crystal materials and polycrystal ceramics are analysed. Electric and magnetic coupling properties are considered. Colour Symmetry Groups and Texture Analysis tool are emploed. Symmetry conditions for polarisation vectors and inverse pole figures related to Aurivillius phases are given. The influence of crystallographic texture of the physical properties of polycrystalline Aurivillius ceramics is evaluated.

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저압 화학기상증착법을 이용한 β-SiC의 증착 및 결정 성장 방위에 따른 기계적 특성 변화 (Deposition of β-SiC by a LPCVD Method and the Effect of the Crystallographic Orientation on Mechanical Properties)

  • 김대종;이종민;김원주;윤순길;박지연
    • 한국세라믹학회지
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    • 제50권1호
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    • pp.43-49
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    • 2013
  • ${\beta}$-SiC was deposited onto a graphite substrate by a LPCVD method and the effect of the crystallographic orientation on mechanical properties of the deposited SiC was investigated. The deposition was performed at $1300^{\circ}C$ in a cylindrical hot-wall LPCVD system by varying the deposition pressure and total flow rate. The texture and crystallographic orientation of the SiC were evaluated by XRD. The deposition rate increased linearly with the gas flow rate from 800 sccm to 1600 sccm. It also increased with the pressure but became saturated above a total pressure of 3.3 kPa. In the range of 3.3 - 10 kPa, the preferred orientation changed from the (220) and (311) planes to the (111) plane. The hardness and elastic modulus showed maximum values when the SiC had the (111) preferred orientation, though it gradually decreased upon a change to the (220) and (311) preferred orientations.