A method of making a FET includes forming a gate structure (18), then etching cavities on either side. A SiGe layer (22) is then deposited on the substrate (10) in the cavities, followed by an Si layer (24). A selective etch is then carried out to etch away the SiGe (22) except for a part of the layer under the gate structure (18), and oxide (28) is grown to fill the resulting gap. SiGe source anddrains are then deposited in the cavities. The oxide (28) can reduce junction leakage current.