Materials Design on the Origin of Gap States in a High-κ/GaAs Interface. (September 2015)

• Record Type: Journal Article
• Authors: Wang, Weichao; Gong, Cheng; Xiong, Ka; Santosh, K.C.; Wallace, Robert M.; Cho, Kyeongjae
• Is Part Of: Engineering. Volume 1:Number 3(2015)
• Page Start: 372
• Page End: 377
• Publication Date: 2015-09
• Subjects: high-mobility device -- high-κ/III-V interface -- interfacial gap states -- first-principle calculations; Engineering -- Periodicals; Engineering -- China -- Periodicals; 620.005
• DOI: 10.15302/J-ENG-2015052
• Languages: English
• ISSNs: 2095-8099

Abstract

ABSTRACT: 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.