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.