HfTiO高κ栅介质Ge MOS电容特性研究

Study on Characteristics of Ge MOS Capacitor with HfTiO High κ Gate Dielectric

采用反应磁控共溅射方法在Ge衬底上制备亚-nm等效氧化物厚度(EOT)的HfTiO高κ栅介质薄膜,研究了湿N2和干N2气氛退火对GeMOS电容电特性的影响。隧穿电子显微镜、椭偏仪、X射线光电子频谱、原子力显微镜以及电特性的测量结果分别表明,与干N2退火比较,湿N2退火能明显抑制不稳定的低κGeOx界面层的生长,从而减小栅介质厚度,降低栅介质表面粗糙度,有效提高介电常数,改善界面质量和栅极漏电流特性,这都归因于GeOx的易水解性。还研究了Ti靶溅射功率对HfTiO栅介质GeMOS器件性能的影响。

Reactive co-sputtering method for growth of sub-nm equivalent oxide thickness （EOT） HfTiO high κ gate dielectric on Ge substrate and the effects of wet or dry N2 annealing on dielectric performances are analyzed. Measuring by transmission-electron microscopy, ellipsometry, X-ray photoelectron spectroscopy, atomic force microscopy and electrical properties indicate that, as compared to dry N2 annealing, the wet N2 annealing can greatly suppress the growth of unstable low-κ GeOx interlayer, resulting in smaller oxide thickness and surface roughness, thus increasing permittity, improving interface quality and gate leakage current. All these are attributed to the hydrolysable property of of GeOx in water-vapor-ambient. Impacts of sputtering power of Ti target on Ge MOS characteristic are investigated too.