Study of epitaxial SrTiO3 (STO) thin films grown on Si(0 0 1)–2 × 1 substrates by molecular beam epitaxy
Study of epitaxial SrTiO3 (STO) thin films grown on Si(0 0 1)–2 × 1 substrates by molecular beam epitaxy
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DOI：
10.1016/s0169-4332(03)00452-5
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发表时间：
2003-06
影响因子：
6.7
通讯作者：
Md. Nurul Kabir Bhuiyan;A. Matsuda;T. Yasumura;T. Tambo;C. Tatsuyama
中科院分区：
文献类型：
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作者：
Md. Nurul Kabir Bhuiyan;A. Matsuda;T. Yasumura;T. Tambo;C. Tatsuyama
采用分子束外延（MBE）技术，在9.0×10−8Torr的o2气氛下，在500°C下，利用Sr和Ti共蒸发，在Si（001）衬底上外延生长出了厚度分别为30、100、300和1000Å的钙钛矿型氧化物SrTiO3（STO）薄膜。SrO缓冲层100Å在350°C下生长在Si衬底上。利用反射高能电子衍射（RHEED）、x射线衍射（XRD）和原子力显微镜（AFM）研究了srtio3薄膜与STO薄膜厚度的关系。在化学清洗和形成保护性sio2层后，通过800°C在Sr下加热Si（001）衬底2min，观察到原子清洁的Si(001) -2 × 1表面的RHEED图案。30和100Å-thick STO薄膜生长后，RHEED模式变得不清晰。相反，在300和1000Å-thick薄膜上，可以清晰地观察到斑点和条纹图案，斑点图案。在800℃退火后，所有样品的表面结晶度都有所提高。在原子力显微镜图像中，厚度为30和1000Å的STO薄膜由颗粒组成。厚度为100-300Å的STO膜的平整度和结晶度均优于其他膜。
Perovskite-type oxide SrTiO3(STO) thin films with thicknesses of 30, 100, 300 and 1000Å have been grown epitaxially on Si(001) substrates using co-evaporation of Sr and Ti in an O2atmosphere of 9.0×10−8Torr at 500°C by molecular beam epitaxy (MBE). SrO buffer layers of 100Å have been grown at 350°C on Si substrates. The SrTiO3films have been studied using reflection high-energy electron diffraction (RHEED), X-ray diffraction (XRD) and atomic force microscopy (AFM) as a function of the thickness of STO films. By heating the Si(001) substrates at 800°C under Sr exposure for 2min after the chemical cleaning and formation of protective SiO2layer, RHEED patterns of the atomically clean Si(001)–2 × 1 surface have been observed. RHEED pattern becomes unclear after the growth of 30 and 100Å-thick STO films. On the contrary, spotty and streaky patterns, and spotty patterns are observed clearly for 300 and 1000Å-thick films, respectively. The surface crystallinity improves for all the samples after annealing at 800°C. The STO films with thicknesses of 30 and 1000Å consist of grains in the images of atomic force microscopy. The flatness and crystallinity of STO films with the thickness of 100–300Å are better than the other films.