The present disclosure provides a bio-field effect transistor (BioFET) and a method of fabricating a BioFET device. The method includes forming a BioFET using one or more process steps compatible with or typical to a complementary metal-oxide-semiconductor (CMOS) process. The BioFET device includes a substrate, a transistor structure, an isolation layer, an interface layer in an opening of the isolation layer, and a metal crown structure over the interface layer. The interface layer and the metal crown structure are disposed on opposite side of the transistor from a gate structure.
