C掺杂TiO薄膜的制备及其第一性原理研究

TiO在微电子结构器件中有重要的应用前景. 本文以CO₂作反应气体, 采用直流反应磁控溅射方法成功制备出C掺杂TiO薄膜. 采用XRD, XPS和四探针电阻计对薄膜结构、成分和电阻率进行表征. 在实验结果的基础之上建立起TiO和C掺杂TiO的计算模型并采用第一性原理 方法计算其能带结构和电子态密度. 实验结果表明薄膜相结构为面心立方的岩盐结构, C取代O的阴离子掺杂为主要掺杂方式, 薄膜电阻率为52.2 μΩ·cm. 第一性原理计算结果表明, 费米能级穿过TiO的导带, TiO具有金属性导电的能带结构特征; C掺杂TiO 后, 其金属性导电的能带结构没有改变, 只是在费米面附近出现C 2p态提供的杂质能级, 杂质能级扩展了TiO的导带宽度并提高了费米面附近的电子能态密度, 从而导至TiO电导增加, 电阻率降低. 第一性原理计算结果与实验结果一致. 关键词： C掺杂TiO 直流反应磁控溅射 第一性原理 电子结构

Deposition and first-principles caculation of carbon-doped titanium monoxide films

Carbon-doped titanium monoxide films were successfully fabricated using CO₂ as reactive gas by means of DC reactive magnetron sputtering. Phase tructure, composition and resistivity of the fabricated films were investigated by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and four point probe method. Results show that the fabricated film has a cubic phase structure, and the carbon element exists mainly as anion in the lattice of C-TiO. The resistivity of C-TiO is 52.2 μΩ·cm which is lower than that of pure TiO. Results of first principles calculation show that the Fermi levels of both TiO and C-TiO lie in their conduction bands, thus TiO and C-TiO have characteristics of metal conduction. Also the results of first principles calculation show that impurity levels of C 2p lie near the conduction band of C-TiO, which extend the width of conduction band and increase the density of states near the Fermi level of C-TiO, so the conductivity of C-TiO is larger than that of undoped TiO. The theoretical calculations are in agreement with experiment results.
Keywords： carbon-doped TiO DC reactive magnetron sputtering first principle electronic structure