基于高κ/GaAs界面态起源的材料设计
Weichao Wang , Cheng Gong , Ka Xiong , Santosh K.C. , Robert M. Wallace , Kyeongjae Cho
工程(英文) ›› 2015, Vol. 1 ›› Issue (3) : 372 -377.
基于高κ/GaAs界面态起源的材料设计
Materials Design on the Origin of Gap States in a High-κ/GaAs Interface
为了满足微电子器件不断扩展到更小尺寸的需求,SiO2栅极介电层被高介电常量材料Hf(Zr)O2所替代,以尽可能减少流过介电薄膜的漏电流。然而,与高介电常量 (高κ) 电介质连接时,传统Si通道中的电子迁移率由于库仑散射、表面粗糙度散射、远程声子散射和介电电荷捕获而有所下降。III-V和Ge是两个有希望的候选材料,其迁移率均优于Si。尽管如此,与Si基界面相比,Hf(Zr)O2/III-V(Ge) 的界面结合更为复杂。成功制造高质量器件关键在于优化器件界面设计时对Hf(Zr)O2/III-V(Ge) 界面结合结构的理解与设计。因此,从原子尺度准确了解界面结合与界面态形成的机制变得尤为重要。在本文中,笔者利用第一性原理计算方法,对HfO2与GaAs之间的界面性质进行了研究。结果表明,隙间态主要由As—As二聚物键合、Ga部分氧化( 在3+和1+之间) 和Ga—悬挂键贡献。这些研究成果能为最优化界面钝化提供重要的指导意见。
Given the demand for constantly scaling microelectronic devices to ever smaller dimensions, a SiO2 gate dielectric was substituted with a higher dielectric-constant material, Hf(Zr)O2, in order to minimize current leakage through dielectric thin film. However, upon interfacing with high dielectric constant (high-κ) dielectrics, the electron mobility in the conventional Si channel degrades due to Coulomb scattering, surface-roughness scattering, remote-phonon scattering, and dielectric-charge trapping. III-V and Ge are two promising candidates with superior mobility over Si. Nevertheless, Hf(Zr)O2/III-V(Ge) has much more complicated interface bonding than Si-based interfaces. Successful fabrication of a high-quality device critically depends on understanding and engineering the bonding configurations at Hf(Zr)O2/III-V(Ge) interfaces for the optimal design of device interfaces. Thus, an accurate atomic insight into the interface bonding and mechanism of interface gap states formation becomes essential. Here, we utilize first-principle calculations to investigate the interface between HfO2 and GaAs. Our study shows that As−As dimer bonding, Ga partial oxidation (between 3+ and 1+) and Ga− dangling bonds constitute the major contributions to gap states. These findings provide insightful guidance for optimum interface passivation.
高迁移率器件 / 高κ/III-V界面 / 界面态 / 第一性原理计算方法
high-mobility device / high-κ/III-V interface / interfacial gap states / first-principle calculations
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