具有Al2O3阻挡层的HfO2栅介质膜的界面和电学性能的表征

Interfacial and Electrical Characterization of HfO2 Gate Dielectric Film with a Blocking Layer of Al2O3

摘要:

研究了经过700 ℃快速热退火的并在Si界面处插入Al2O3阻挡层的HfO2栅介质膜的界面结构和电学性能。X射线光电子谱表明，退火后，界面层中的SiOx转化为化学当量的SiO2，而且未发现铪基硅酸盐和铪基酸化物。由电学测试提取出等效栅氧厚度为2.5 nm, 固定电荷密度为–4.5×1011/cm2。发现Al2O3阻挡层能有效地阻止Si原子扩散进入HfO2薄膜，进而改善HfO2栅介质膜的界面和电学性能

Abstract:

HfO2 gate dielectric films with a blocking layer of Al2O3 inserted between HfO2 layer and Si layer (HfO2/Si) were treated with rapid thermal annealing process at 700 ℃. The interfacial structure and electrical properties were reported. The results of X-ray photoelectron spectroscopy showed that the interfacial layer of SiOx transformed into SiO2 after the annealing treatment, and Hf-silicates and Hf-silicides were not detected. The results of high-resolution transmission electron microscopy indicated that the interfacial layer was composed of SiO2 for the annealed film with blocking layer. The results of the electrical measurements indicated that the equivalent oxide thickness decreased to 2.5 nm and the fixed charge density decreased to –4.5×1011/cm2 in comparison with the same thickness of HfO2 films without the blocking layer. Al2O3 layer could effectively prevent the diffusion of Si into HfO2 film and improve the interfacial and electrical performance of HfO2 film