Nanolaminated Al₂O₃/HfO₂ dielectrics for silicon carbide based devices

Nanolaminated aluminum oxide (Al₂O₃)/hafnium oxide (HfO₂) thin films as well as single Al₂O₃ and HfO₂ layers have been grown as gate dielectrics by the plasma enhanced atomic layer deposition technique on silicon carbide (4H-SiC) substrates. All the three dielectric films have been deposited at a temperature as low as 250 °C, with a total thickness of about 30 nm, and, in particular, the nanolaminated Al₂O₃/HfO₂ films have been fabricated by alternating nanometric Al₂O₃ and HfO₂ layers. The structural characteristics and dielectric properties of the nanolaminated Al₂O₃/HfO₂ films have been evaluated and compared to those of the parent Al₂O₃ and HfO₂ single layers. Moreover, the structural properties and their evolution upon annealing treatment at 800 °C have been investigated as a preliminar test for their possible implementation in the device fabrication flow chart. On the basis of the collected data, the nanolaminated films demonstrated to possess promising dielectric behavior with respect to the simple oxide layers.