Ahn Joonsung, Kim Tae Whan
Department of Electronics and Computer Engineering, Hanyang University, Seoul 04763, Korea.
J Nanosci Nanotechnol. 2018 Sep 1;18(9):6014-6016. doi: 10.1166/jnn.2018.15576.
Carrier transport mechanisms via a high-k gate dielectric material of hafnium dioxide (HfO2) between III-V GaAs were investigated by using a non-equilibrium Green's function (NEGF). The full band structure for the HfO2 layer was determined by using a sp3d5s* closest neighbor empirical tight-binding model. The band structure of the GaAs bulk was determined by using an empirical tight-binding model. The tunneling currents dependent on the thickness of the HfO2 layer with a GaAs layer were obtained by solving the NEGF in an open boundary condition. The applied voltage to obtain the tunneling currents through the HfO2 layer between the GaAs layers was higher than that for the Si/HfO2/Si structure. This was due to the much smaller energy difference between the conduction band edge (Ec) and the Fermi level (Ef) of the Si layer than that of the GaAs layer. The GaAs/HfO2/GaAs structure showed an increase in the leakage current in comparison with the Si/HfO2/Si structure.
通过使用非平衡格林函数（NEGF）研究了III-V族砷化镓（GaAs）之间经由二氧化铪（HfO2）这种高k栅极介电材料的载流子输运机制。利用sp3d5s*最近邻经验紧束缚模型确定了HfO2层的全带结构。利用经验紧束缚模型确定了块状GaAs的能带结构。通过在开放边界条件下求解NEGF获得了与GaAs层相关的依赖于HfO2层厚度的隧穿电流。为使隧穿电流通过GaAs层之间的HfO2层而施加的电压高于Si/HfO2/Si结构的电压。这是由于Si层的导带边缘（Ec）与费米能级（Ef）之间的能量差比GaAs层的小得多。与Si/HfO2/Si结构相比，GaAs/HfO2/GaAs结构的泄漏电流有所增加。
