Microwave dielectric characterisation of SiO2 thin films through a single MIM test structure

Abstract

A microwave dielectric characterisation procedure only employing a single metal-insulator-metal (MIM) structure is presented to extract accurately dielectric properties of SiO2 thin films deposited on Pt/SiO2/Si substrate up to 1GHz. The procedure is a one-port reflection measurement. And the reflection coefficient S11 of the microwave signal is extracted during the measurement by the vector network analyzer accompanied with the microprobes. An equivalent circuit model of MIM structure is built to eliminate the parasitic effect existing in the structure. The admittance parameter that represents the intrinsic properties of the dielectric thin films is obtained by analyzing the equivalent circuit model physically and dealing with the physical equations masterly. The dielectric properties of SiO2 thin films extracted from the admittance without parasitic effect can match with the reference value favorably in measurement frequency range, which indicates that the parasitic effect is corrected effectively. Evidently, the method is of feasibility and expected to employ in the microwave dielectric characterisation of the novel high-K dielectric thin films promoting the development of microwave industry.