Room-Temperature Cosputtered HfO[sub 2]–Al[sub 2]O[sub 3] Multicomponent Gate Dielectrics

Hafnium oxide–aluminum oxide (HfAlO) dielectric films were cosputtered using HfO 2 and Al 2 O 3 targets, and their properties are studied in comparison with pure HfO 2 films. The X-ray diffraction studies confirmed that the HfO 2 films are nanocrystalline with a monoclinic phase. The as-deposited HfAlO films with a chemical composition of ( HfO 2 ) 0.86 ( Al 2 O 3 ) 0.14 are amorphous even after annealing at 500 ° C . Further, the cosputtered films show a slight reduction in leakage current. The leakage current density may be significantly reduced below 3 × 10 − 10 A cm − 2 at an electric field of 0.25 MV/cm when applying the proper radio-frequency bias to the substrate.