A correlation of capacitive RF-MEMS reliability to AlN dielectric film spontaneous polarization

This paper investigates the effect of spontaneous polarization of magnetron-sputtered aluminum nitride on the electrical properties and reliability of Radio Frequency - Micro-Electro-Mechanical Systems capacitive switches. The assessment is performed with the aid of application of thermally stimulated polarization currents in metal-insulator-metal capacitors and temperature dependence of device capacitance. The study reveals the presence of a surface charge, which is smaller than that expected from material spontaneous polarization, but definitely is responsible for the low degradation rate under certain bias polarization life tests.