HiGH-kappa; MIM capacitors with atomic-layer-deposited HfO 2-Al2O3 laminated and sandwiched dielectrics for analog circuit applications

Abstract

Metal-Insulator-Metal (MIM) capacitors with atomic-layer-deposited (ALD) HfO2-Al2O3 laminated and sandwiched dielectrics have been compared for analog circuit applications. The experimental results indicate that significant improvements have been achieved using the laminated dielectrics, including extremely low leakage current of 1times;10-9A/cm2 at 3.3V and 125deg;C, high breakdown electric field of sim;3.3MV/cm at 125deg;C, good polarity-independent electrical characteristics, while retaining relatively high capacitance density of 3.13fF/mu;m2 as well as voltage coefficients of capacitance as low as -80ppm/V and 100ppm/V2 at 100kHz. The superiority of the laminated dielectrics results from the alternate insertion of Al 2O3 layers into bulk HfO2, inhibiting crystallization of HfO2 due to thinning of each HfO2 layer and blocking the grain boundary channels extending from top to bottom, as well as good interfacial quality because of multilayer blockage effect of Al2O3 to impurity diffusion.