Effects of Al2O3 on Thermal Stability and Electrical Reliability of HfO2 Film on Strained SiGe

摘要:

研究了阻挡层Al2O3对应变SiGe上HfO2 薄膜的热稳定性和电学可靠性的影响。高分辨透射电镜(HRTEM)像表明，阻挡层使HfO2在700 °C温度下退火后仍然是非晶的。散能X射线谱(EDS)分析表明，阻挡层抑制了Si原子在HfO2薄膜中的扩散。X射线光电子谱(XPS)测试表明，阻挡层抑制了界面处HfSiO和GeOx的生长。电学测试分析说明，带有阻挡层的MIS电容的电学性能得到提高，包括60Co γ射线辐射后较高的电容密度、较低的缺陷密度、以及较小的平带电压漂移。

Abstract:

The thermal stability and the electrical reliability of HfO2 films with a blocking layer (BL) of Al2O3 on strained Si0.8Ge0.2 were studied. High-resolution transmission electron microscopy (HRTEM) indicates that BL keeps HfO2 amorphous after 700 °C annealing treatment. Energy dispersive X-ray spectroscopy (EDS) shows that BL can suppress Si diffusion in HfO2 films effectively. X-ray photoelectron spectroscopy (XPS) suggests that BL suppresses the growth of HfSiO and GeOx. Electrical measurements show that the reliability of the sample with BL is improved, including high capacitance density, low interface defect density, and small shift of flatband voltage after total-dose 60Co γ-ray irradiation.