Characteristics of interface between Ta2O5 thin film and Si (100) substrate

Control of the interface between Ta2O5 gate dielectric and Si substrate is considered to be one of the most challenging issues for good device performance. In this work, tantalum pentoxide (Ta2O5) thin films were fabricated using a magnetron sputtering system and the influence of the substrate bias and deposition temperature on the interfacial characteristics of Ta2O5 thin films on Si was investigated by systematically deconvoluting the RBS data and C-V curves. Our results show that the thickness of the interfacial layer remains about the same at different substrate biases and as the deposition temperature increases, the interfacial layer between Ta2O5 and Si (100) thickens slightly. These suggest that substrate bias assistance is an effective method to improve the structural and dielectric properties of Ta2O5/Si thin films. The effects and mechanism of substrate biasing on the interfacial layer are also described.