Abstract

Epitaxial SrTiO ₃ thin films were grown by molecular beam epitaxy (MBE) using an oxygen plasma source. SrO and TiO₂ layers were alternately deposited on 0.5 wt% (001) Nb doped SrTiO₃ substrates whose surface were terminated with TiO₂. A two-dimensional (2-D) layer-by-layer growth mode was confirmed by the reflection high energy electron diffraction (RHEED) oscillation during the growth and the well-terraced SrTiO₃ surface was obtained after growth. X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM) analysis showed that the obtained SrTiO₃ thin films had epitaxially (001) oriented and stoichiometric crystal structures without any interfacial layer. With simple MIS (Metal-Insulator-Semiconductor) capacitors using Ir top electrodes, the dielectric constants of the SrTiO₃ thin film with 10, 15, 20, 100 nm were measured at room temperature, 10 kHz and zero bias.

摘要

使用氧等离子体源通过分子束外延（MBE）生长外延SrTiO ₃薄膜。将SrO和TiO ₂层交替沉积在0.5 wt％（001）掺Nb的SrTiO ₃衬底上，该衬底的表面被TiO ₂终止。通过在生长过程中的反射高能电子衍射（RHEED）振荡证实了二维（2-D）逐层生长模式，并且在生长后获得了高阶的SrTiO ₃表面。X射线衍射（XRD）和扫描透射电镜（STEM）分析表明，所得SrTiO ₃ 薄膜具有外延（001）取向和化学计量的晶体结构，没有任何界面层。使用使用Ir顶部电极的简单MIS（金属-绝缘体-半导体）电容器，可以在室温，10 kHz和零偏压下测量10、15、20、100 nm的SrTiO ₃薄膜的介电常数。