HfGdO/Ge异质结的制备及其能带排列

Preparation and Band Alignments of HfGdO/Ge Heterojunctions

HfO_2是一种很有应用前景的高k栅介质材料,稀土元素掺杂可以有效改进HfO_2的性能。采用磁控溅射方法制备了Ge基HfGdO薄膜,即HfGdO/Ge异质结。X射线衍射结果显示这种方法制备的薄膜是非晶结构,利用原子力显微镜对退火前后薄膜的表面形貌进行了观察,俄歇电子能谱结果发现制备的薄膜是符合化学计量比的。通过X射线光电子能谱(XPS)对薄膜的禁带宽度和它相对于Ge衬底的导带、价带偏移进行了研究,结果显示其禁带宽度为(5.86±0.2)eV,HfGdO/Ge结构的价带偏移和导带偏移分别是(3.6±0.2)eV和(1.6±0.3)eV。这些数据将为HfGdO薄膜在栅介质上的应用提供理论依据。

HfO_2 is one of the promising high-k gate dielectric materials.The physical properties of the HfO_2 can be improved by doping rare earth elements.The Ge based HfGdO thin film was prepared by the magnetron sputtering,i.e.the HfGdO heterojunction film.The X-ray diffraction result shows that the film is of amorphous structure.The surface morphologies of the HfGdO films before and after annealing were observed by the atomic force microscopy.The Auger electron spectroscopy measurement result shows that the prepared HfGdO film conforms to the stoichiometric ratio.The energy gap of the HfGdO film and its conduction-band offset and valence-band offset with respect to the Ge substrate were studied by the Xray photoelectron spectroscopy（XPS）.The result shows that the energy gap is（5.86 ± 0.2） eV,the valence-band offset and conduction-band offset for the HfGdO/Ge heterojunction are（3.6 ± 0.2） e V and（1.6 ± 0.3） eV,respectively.These data provide a theoretical basis for the application of HfGdO films on the gate dielectric.