氧化铬外延薄膜的x射线研究  

X-ray study of chromium oxide films epitaxially grown on MgO~*

作　　者：杜晓松[1] S.Hak O.C.Rogojanu T.Hibma 

机构地区：[1]电子科技大学微电子与固体电子学院,成都610054 [2]Material Science Centre,University of Groningen

出　　处：《物理学报》2004年第10期3510-3514,共5页Acta Physica Sinica

基　　金：国家出国留学基金 (批准号 :2 185 10 3 0 );荷兰高等教育国际合作组织 (Nuffic)资助的课题~~

摘　　要：采用分子束外延技术 (MBE)在MgO(0 0 1)基板上沉积了氧化铬薄膜 ,并利用x射线衍射 (XRD)和x射线反射谱(XRR)对薄膜的晶体结构进行了表征 .θ— 2θ扫描和倒易空间图 (RSM)揭示出薄膜为单相c轴外延生长 ,晶体结构为体心正交 ,晶胞常数a ,b ,c分别为 0 894 0± 0 0 0 0 3,0 2 98± 0 0 0 0 2和 0 3897± 0 0 0 0 2nm .扫描表明薄膜在面内具有 90°孪晶 ,取向关系为a∥MgO〈110〉 ,c∥MgO(0 0 1) .XRR谱测得薄膜的电子密度为 135 0± 2 0nm- 3,与由晶胞体积计算得到的电子密度非常吻合 ,表明薄膜的化学成分为Cr2 O3 该物质在结构上等同于沿MgO〈110〉方向存在着1 3有序的Cr空位 。Chromium oxide films grown by molecular beam epitaxy on MgO(001) substrates were characterized by x_ray diffraction (XRD) and x_ray reflectivity (XRR) measurements. The absence of random oriented peaks in the θ—2θ spectra indicated that the thin films were a single phase. Reciprocal space mapping (2θ/ω-Δψ) revealed a (3×1) rectangular superstructure along MgO(110) plane, resulting in a body-centred orthorhombic unit cell with a=0.8940±0.0003 nm, b=0.298 nm, c=0.3897±0.0002 nm, measured by conventional reciprocal space mapping (2θ/ω vs. Δω) and θ—2θ scans. -scan showed two domains apart by 90° with one domain aligned to the MgO substrate as: a∥ MgO(110), c∥ MgO(001). The electron density of the film deduced by the unit cell volume was in good agreement with that from the XRR fittings, indicating that the chemical component of the films were Cr_2O_3. The crystal structure of the films were equivalent to a NaCl-type CrO with 1/3 Cr atoms vacancy along MgO(110) direction in an ordered way.

关 键 词：外延薄膜 电子密度 晶体结构 氧化铬 倒易空间 等同 空位 MBE 反射谱 分子束外延技术 

分 类 号：O434.1[机械工程—光学工程]