A field effect transistor (FET) device, which mitigates leakage current induced along the edges of the FET device, is isolated by shallow trench isolation having a channel width between a first and a second shallow trench at a first and second shallow trench edges. A gate extends across the channel width between the first and second shallow trenches. The gate has a first length at the shallow trench edges and a second length less than the first length between the shallow trench edges. The first length and the second length are related such that the threshold voltage, V.sub.t, at the shallow trench edges is substantially equal to V.sub.t between the shallow trench edges. The gate structure of the FET device is produced using a unique phase shift mask that allows the manufacture of submicron FET devices with very small channel lengths.