title: Optical properties and bandgap evolution of ALD HfSiOx films.
abstract: Hafnium silicate films with pure HfO2 and SiO2 samples as references were fabricated by atomic layer deposition (ALD) in this work. The optical properties of the films as a function of the film composition were measured by vacuum ultraviolet (VUV) ellipsometer in the energy range of 0.6 to 8.5 eV, and they were investigated systematically based on the Gaussian dispersion model. Experimental results show that optical constants and bandgap of the hafnium silicate films can be tuned by the film composition, and a nonlinear change behavior of bandgap with SiO2 fraction was observed. This phenomenon mainly originates from the intermixture of d-state electrons in HfO2 and Si-O antibonding states in SiO2.
authors: Institute of Advanced Nanodevices, School of Microelectronics, Fudan University, No. 220 Handan Road, Shanghai, 200433 China.
authors: Wen
authors: W
authors: Yang
authors: Semiconductor Physics, Technische Universität Chemnitz, Reichenhainer Straße 70, Chemnitz, D-09107 Germany.
authors: Michael
authors: M
authors: Fronk
authors: Institute of Advanced Nanodevices, School of Microelectronics, Fudan University, No. 220 Handan Road, Shanghai, 200433 China.
authors: Yang
authors: Y
authors: Geng
authors: Institute of Advanced Nanodevices, School of Microelectronics, Fudan University, No. 220 Handan Road, Shanghai, 200433 China.
authors: Lin
authors: L
authors: Chen
authors: Institute of Advanced Nanodevices, School of Microelectronics, Fudan University, No. 220 Handan Road, Shanghai, 200433 China.
authors: Qing-Qing
authors: QQ
authors: Sun
authors: Semiconductor Physics, Technische Universität Chemnitz, Reichenhainer Straße 70, Chemnitz, D-09107 Germany.
authors: Ovidiu D
authors: OD
authors: Gordan
authors: Institute of Advanced Nanodevices, School of Microelectronics, Fudan University, No. 220 Handan Road, Shanghai, 200433 China.
authors: Peng
authors: P
authors: Zhou
authors: Semiconductor Physics, Technische Universität Chemnitz, Reichenhainer Straße 70, Chemnitz, D-09107 Germany.
authors: Dietrich Rt
authors: DR
authors: Zahn
authors: Institute of Advanced Nanodevices, School of Microelectronics, Fudan University, No. 220 Handan Road, Shanghai, 200433 China.
authors: David Wei
authors: DW
authors: Zhang
keywords: Bandgap; HfSiOx; VUV