论文标题
未退火后的4H-SIC/SIO $ _2 $接口的原子结构调查的密度功能理论计算
Density functional theory calculations for investigation of atomic structures of 4H-SiC/SiO$_2$ interface after NO annealing
论文作者
论文摘要
我们建议在没有退火后的$ a $，$ m $，c和si面的4H-SIC/SIO $ _2 $接口的原子结构。我们提出的结构优先形成界面的SIC侧的最高层，这与次级离子质谱法的实验发现一致，即n原子在界面处积聚。此外，每个平面的面积N-ATOM密度在10 $^{14} $ ATOM/cm $^2 $的顺序上，这也与实验结果一致。此外，没有退火后的界面的电子结构，其中删除了CO键，并且仅插入界面处的氮化物层没有间隙状态，尽管在没有退火之前的某些界面模型包括由频段gabap的价值带边缘附近的CO键引起的间隙状态。我们的结果表明，没有退火可以通过形成氮化物层来降低界面缺陷的密度。
We propose the atomic structures of the 4H-SiC/SiO$_2$ interface for the $a$, $m$, C, and Si faces after NO annealing. Our proposed structures preferentially form at the topmost layers of the SiC side of the interface, which agrees with the experimental finding of secondary-ion mass spectrometry, that is, the N atoms accumulate at the interface. In addition, the areal N-atom density is on the order of 10$^{14}$ atom/cm$^2$ for each plane, which is also consistent with the experimental result. Moreover, the electronic structure of the interface after NO annealing, in which the CO bonds are removed and the nitride layer only at the interface is inserted, is free from gap states, although some interface models before NO annealing include the gap states arising from the CO bonds near the valence band edge of the bandgap. Our results imply that NO annealing can contribute to the reduction in the density of interface defects by forming the nitride layer.
