HfON/LaON as charge-trapping layer for nonvolatile memory applications

The charge-trapping characteristics of HfON/LaON composite film (denoted as HfLaON) were investigated based on an Al/Al₂O₃/HfLaON/SiO₂/Si (MONOS) capacitor. The physical properties of the high-k film were analyzed by transmission electron microscopy and electron diffraction spectroscopy. Compared with another MONOS capacitor with nitrided La₂O₃ as charge-trapping layer, the one with HfLaON showed better memory characteristics in terms of larger memory window, higher program speed (6.3 V at +14 V for 100 μs), and smaller charge loss (8.2% after 10⁴ sec), due to the HfLaON composite film exhibiting an amorphous structure and the suppressed formation of an interlayer at the HfLaON/SiO₂ interface.