High Q inductor and its forming method

摘要

A high Q inductor and its forming method is disclosed. In this forming method, a semiconductor substrate is first provided with a trench formed thereon. The trench is defined by dry etching and formed to a depth of 3~5 mum. A material having a higher resistivity than that of the semiconductor is then provided to fill the trench. The material can be formed by first depositing an epitaxy layer with a lower dopant concentration than that of the semiconductor substrate by several orders of magnitude on the semiconductor substrate, then etching back the epitaxy layer to expose the surface of the semiconductor substrate. Thereafter, a dielectric layer is formed on the semiconductor substrate and the trench, and an inductor winding is formed on the dielectric layer above the trench to form the high Q inductor.