A fin field effect transistor (FinFET) structure and method of making the FinFET including a silicon fin that includes a channel region and source/drain (S/D) regions, formed on each end of the channel region, where an entire bottom surface of the channel region contacts a top surface of a lower insulator and bottom surfaces of the S/D regions contact first portions of top surfaces of a lower silicon germanium (SiGe) layer. The FinFET structure also includes extrinsic S/D regions that contact a top surface and both side surfaces of each of the S/D regions and second portions of top surfaces of the lower SiGe layer. The FinFET structure further includes a replacement gate or gate stack that contacts a conformal dielectric, formed over a top surface and both side surfaces of the channel region.