退火对非晶Al2O3高k栅介质薄膜特性的影响

利用射频反应溅射方法制备了Al2O3非晶薄膜,用椭圆偏振仪获得了薄膜的厚度,用高频C-V和变频C-V及J-V测量了薄膜的电学特性,用X射线以衍射(XRD)检测了薄膜的结构,用原子力显微镜(AFM)观察了薄膜的表面形貌.实验得到了电学特性优异的薄膜样品,对薄膜的退火研究发现,氮气低温退火使Al2O3薄膜的介电常数得到了提高并使漏电流特性得到了改善.可以认为,氮气退火消除了薄膜中原有的缺陷,并使得薄膜更加致密是主要的原因,而过高温度的退火会导致氧化铝中少量的氧的损失,从而导致了氧化铝层中固定电荷密度的增大,进而出现了大的平带电压.XRD显示样品的非晶特性非常稳定,AFM显示薄膜表面非常平整,能够满足大规模集成电路短期的发展需要.

Effect of Annealing on AL2O3 Amorphous High-k Gate Dielectric Films Properties

Amorphous Al2O3 dielectric films have been fabricated by reactive radio frequency sputtering method.Grazing angle incidence x-ray diffraction results show that the as-deposited and annealed films are amorphous.Atomic force microscope has been applied to observe the surface morphology of the thin film.The electric CV and I-V characteristics are measured at high and variable frequencies,respectively.It is found that the films show excellent electric properties.The dielectric constant k of the films increases with increasing annealing temperature in N2.It may be accounted that N2 annealing can eliminate defects in the Al2O3 dielectric films and make the films compacter.But the loss of oxygen will cause a high density of fixed charge and a big unacceptable negative flat voltage at high temperatures.The films are very smooth which meets the requirements of the device.