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, that is disposed above the lower insulator and not above the first and second portions of the lower SiGe layer, in which the gate stack is electrically insulated from the extrinsic S/D regions by the conformal dielectric.