High Q spiral-type microinductors on silicon substrates

Although integrated microinductors are in high demand for high frequency applications, their usefulness is limited due to their poor performance (e.g., low Q-factor, low inductance, and high parasitics). To expand the range of applicability of integrated microinductors at high frequencies, their electrical characteristics, especially quality factor and inductance, must be improved. In this research, integrated spiral-type microinductors suspended above the silicon substrate using surface micromachining and electroplating techniques are investigated. The silicon substrate used has resistivity ranging from 3 similar to 7 ohms-cm and thickness ranging from 330 mu m similar to 430 mu m. These fabricated inductors have inductance ranging from 10 similar to 25 nH and Quality factor ranging from 14 similar to 18.