A metal oxide semiconductor field effect transistor preferably fabricated with a silicon-on-insulator process has a first semiconductor region and a second semiconductor region in a spaced relationship thereto A body structure is defined by a channel segment between the first semiconductor region and the second semiconductor region, and a first extension segment structurally contiguous with the channel segment. A shallow trench isolation structure surrounds the first semiconductor region, the second semiconductor region, and the body structure, with a first extension interface being defined between the shallow trench isolation structure and the first extension segment of the body structure to reduce leakage current flowing from the second semiconductor region to the first semiconductor region through a parasitic path of the body structure.