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 degrees 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 degrees 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.