Effect of Single SiO 2 Layer Incorporation on Electrical Performances of Metal-insulator-metal Capacitors with Al 2 O 3-HfO 2-Al 2 O 3 Dielectrics

The metal-insulator-metal (MIM) capacitors with Al2O3/HfO2/Al2O3 (AHA) and Al2O3/HfO2/SiO2/HfO2/Al2O3 (AHSHA) dielectric structure using atomic layer deposition (ALD) technique have been fabricated. It is demonstrated that the dielectric loss at higher applied frequency and quadratic VCC in high-κ MIM capacitors can be decreased by means of introducing an ultrathin layer of ALD SiO2, which has an opposite sign of quadratic VCC against the HfO2 layers. A high capacitance density of 8.1 fF/μm 2 and the low leakage current density of 2.5 10-7 A/cm 2 at 1 MV/cm can be achieved with the dielectric structure as AHSHA. In addition, the breakdown electrical field in AHSHA dielectric is obviously improved. Furthermore, with the survey of different leakage models, the Schottky emission has been considered as the dominating conduction mechanism for both of the AHA and AHSHA capacitors.