Effect of annealing on interfacial and band alignment characteristics of HfO2/SiO2 gate stacks on Ge substrates

• Published in: Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena Microelectronics and nanometer structures processing, measurement and phenomena, 2012-01, Vol.30 (1)
• Main Authors: Li, Xue-Fei, Liu, Xiao-Jie, Fu, Ying-Ying, Li, Ai-Dong, Zhang, Wen-Qi, Li, Hui, Wu, Di
• Format: Article
• Language: English
• ISSN: 1071-1023; 2166-2746; 1520-8567; 2166-2754
• DOI: 10.1116/1.3665416

The authors have investigated the effect of 500 °C annealing for 60 s in N2 on interfacial and band alignment characteristics of HfO2/SiO2 gate stacks on n-type Ge substrates. X-ray photoelectron spectroscopy analyses reveal that the SiO2 interlayer can effectively suppress Ge outdiffusion during HfO2 growth and subsequent postdeposition annealing process. The electrical measurement shows that capacitance equivalent thickness of 1.75 nm and a leakage current density of 3.9 × 10−3 A/cm2 at gate bias of flatband voltage (V fb) + 1 V was obtained for the annealed sample. The conduction band offsets at the HfO2/SiO2/Ge with and without annealing are found to be 2.22 and 2.07 eV, respectively.