A method of forming a MOSFET device is provided including: providing an SOI wafer; forming a dummy gate oxide and dummy gates on portions of the SOI layer that serve as channel regions of the device; forming spacers and doped source/drain regions in the SOI layer on opposite sides of the dummy gates; depositing a gap fill dielectric; removing the dummy gates/gate oxide; recessing areas of the SOI layer exposed by removal of the dummy gates forming one or more u-shaped grooves that extend part-way through the SOI layer such that a thickness of the SOI layer remaining in the channel regions is less than a thickness of the SOI layer in the doped source/drain regions under the spacers; and forming u-shaped replacement gate stacks in the u-shaped grooves such that u-shaped channels are formed in fully depleted regions of the SOI layer adjacent to the u-shaped replacement gate stacks.