Comparison of Multilayer Dielectric Thin Films for Future Metal--Insulator--Metal Capacitors: Al2O3/HfO2/Al2O3 versus SiO2/HfO2/SiO2

In this paper, two kinds of multilayered metal--insulator--metal (MIM) capacitors using Al 2 O 3 /HfO 2 /Al 2 O 3 (AHA) and SiO 2 /HfO 2 /SiO 2 (SHS) were fabricated and characterized for radio frequency (RF) and analog mixed signal (AMS) applications. The experimental results indicate that the AHA MIM capacitor (8.0 fF/μm 2 ) is able to provide a higher capacitance density than the SHS MIM capacitor (5.1 fF/μm 2 ), while maintaining a low leakage current of about 50 nA/cm 2 at 1 V. The quadratic voltage coefficient of capacitance, $\alpha$ gradually decreases as a function of stress time under constant voltage stress (CVS). The parameter variation of SHS MIM capacitors is smaller than that of AHA MIM capacitors. The effects of CVS on voltage linearity and time-dependent dielectric breakdown (TDDB) characteristics were also investigated.