Application of ALD high-k Dielectric Films as Charge Storage Layer and Blocking Oxide in Nonvolatile Memories

ALD high-k dielectric films of HfO2 were utilized for the charge trapping layer and Al2O3 for the blocking oxide layer during fabrication of several Metal/Al2O3/HfO2/SiO2/Si (MAHOS) nonvolatile memory (NVM) cells based on Si nanowire channel. Si nanowires grown from predefined Au catalysts were integrated into memory devices by using a self-aligning approach. For benchmarking and comparison a different Metal/SiO2/HfO2/SiO2/Si (MOHOS) nonvolatile memory cell with a SiO2 blocking layer was also processed. All the Si nanowire nonvolatile memory cells show a large memory window, good endurance and retention, however, the MAHOS cells with Al2O3 blocking layers outperform the MOHOS cell with SiO2 blocking layer.