Techniques for notifying at least one entity of an occurrence of an event in an audio signal are provided. A gate electrode of a p-type MIS transistor includes a conductive coating film, which is formed in contact with the gate insulation film and has a Fermi level on a valence band side from a substantial center of the band gap of the semiconductor substrate, and the second metal-containing film formed on the conductive coating film and having a lower resistance than the conductive coating film. The advantage of the invention is that a homogenous flanged bearing ring is obtained in a simple and cost-effective way.