A Study of Dielectric Relaxation and Capacitance Matching of ${rm Al}_{2}{rm O}_{3}/{rm HfO}_{2}/{rm Al}_{2}{rm O}_{3}$ MIM Capacitors

摘要

Key analog characteristics such as dielectric relaxation and capacitance matching for ${rm Al}_{2}{rm O}_{3}/{rm HfO}_{2}/{rm Al}_{2}{rm O}_{3}$ (AHA) metal-insulator-metal (MIM) capacitors were analyzed for high-performance analog circuit applications. Although the dc characteristics of AHA MIM capacitor were acceptable for analog operation, the variation of the quadratic voltage coefficient $(alpha)$ under constant voltage stress (CVS) and the dielectric relaxation remained problematic. The dependence of $alpha$ for AHA MIM capacitor decreased gradually under CVS and the dielectric relaxation of AHA MIM capacitor was greater than that of conventional MIM capacitor, which was due to the effect of preexisted traps in high-$k$ dielectric. The extracted matching coefficient of AHA MIM capacitor was, however, 0.698% $mu{rm m}$, which was low enough to be used for analog/mixed signal/radio frequency application.