The high-k Metal-insulator-Metal (MIM) capacitor Back-End-of-Line (BEOL) integration into mixed signal and Radio Frequency (RF) circuits is characterized by the effort toward optimizing the capacitance voltage linearity. This letter is focused on the role of the TiOxNy-based interfacial layer with respect to Capacitance-Voltage C(V) curves of Au/HfO2/TiN MIM capacitors. The correlation between the quadratic capacitance-voltage variation and interfacial layer thickness is demonstrated. The quadratic voltage coefficient of the dielectric stack can be reduced by increasing the thickness of the TiOxNy layer. (C) 2009 Elsevier B.V. All rights reserved.