High Q spiral-type microinductors on silicon substrates

Although integrated microinductors are in high demand for high frequency ap plications, their usefulness is limited due to their poor performance (e.g. , low Q-factor, low inductance, and high parasitics). To expand the range o f applicability of integrated microinductors at high frequencies, their ele ctrical 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 electroplatin g techniques are investigated. The silicon substrate used has resistivity r anging from 3 similar to 7 ohms-cm and thickness ranging from 330 mu m simi lar 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.