Theoretical and Experimental Investigation of Thermal Stability of HfO_2/Si and HfO_2/SiO_2 Interfaces

摘要

The assessment of the thermal stability across HfO_2/Si and HfO_2/SiO_2 interfaces has been difficult due to lack of thermodynamic data. In this paper, we present the results of thermodynamie calculations intended to fill this gap. A thermodynamic model was developed by assuming that HfSiO_4 is an ideal solution of HfO_2 and SiO_2 to a first order approximation. The theoretical results predict that the HtO_2/Si interface is thennodynamically stable up to 1100℃, while the HfO_2/SiO_2 interface is thermodynamically unstable even at room temperature. Our experimental results from TEM and XPS analysis are consistent with these modeling predictions.