Y掺杂Al2O3高k栅介质薄膜的制备及性能研究

利用射频反应共溅射方法制备了Y掺杂Al₂O₃电介质薄膜，用掠入射x射线衍射检测了薄膜的结构，用高分辨率扫描电子显微镜(HRSEM)、原子力显微镜(AFM)观察了薄膜断面和表面形貌，用高频C-V和变频C-V及J-V测量了样品的电学特性. 结果表明，Y的掺入使电介质薄膜的介电常数k有了很大提高(8.14—11.8)，并体现出了较好的介电特性. 分析认为：与氧具有较大电负性差的Y离子的加入，增大了薄膜中的金属—氧键(M—O)的强度；同时，Y的加入使Al₂O₃的结构和原子配位发生了改变，从而提高了离子极化对薄膜介电常数的贡献. 退火前后的XRD谱均显示薄膜为非晶态；HRSEM断面和AFM形貌像显示所制备的薄膜非常平整，能够满足器件要求. 关键词： 高k栅介质 掺杂氧化铝 射频反应溅射

Fabrication and properties of the Y-doped Al2O3 high-k gate dielectric films

Y-doped Al₂O₃ dielectric films have been fabricated by reactive radio frequency co-sputtering method. Grazing angle incidence x-ray diffraction results show that the as-deposited and annealed films are amorphous. High resolution scanning electron microscope and atomic force microscope have been applied to observe the cross-section and the surface morphology of the thin films. The electric C-V and I-V characteristics were measured at high and variable frequency, respectively. It was found that the dielectric constant k of the films increases remarkably (from 8.14 to 11.8) with increasing Y-doping concentration. The Y—O bond is stronger than Al—O due to the obvious difference in electro-negativity between the two bond members, which enhanced the ionic polarization in the thin films leading to an increase of the dielectric constant. It was supposed that the presence of Y ions changed the structure and atomic coordination of Al₂O₃. The films were very smooth which meet the requirements of the device.