In-depth investigation of the mechanisms impacting C-V/G-V characteristics of Ge/GeON/HfO2/TiN stacks by electrical modeling

Using C-V and G-V electrical modeling, we give insights on the atypical behavior of C-V characteristics with Ge substrates i.e. the low frequency behavior in strong inversion and the large bumps in the weak inversion region. The modeling of the strong inversion region reveals that a small density of bulk defects - in the range Of 10(15)-10(16).cm(-3) - can explain the low frequency behavior of the C-Vs. The modeling of the depletion region takes into account the specific properties of germanium, especially the fast minority carrier response. It demonstrates that considering the occupation of interface defects by minority carriers is essential to explain the weak inversion bumps. This study also clearly shows that common D-it extraction techniques using C-V and G-V measurement on Si structures are no longer applicable for germanium.