Low resistance field-effect transistors and methods of manufacturing the same are disclosed herein. An example field-effect transistor disclosed herein includes a substrate and a stack above the substrate. The stack includes an insulator and a gate electrode. The example field-effect transistor includes a semiconductor material layer in a cavity in the stack. In the example field-effect transistor, a region of the semiconductor material layer proximate to the insulator is doped with a material of the insulator.