a structure and a method are disclosed of an enhanced t - gate for modulation doped field effect transistors . the enhanced t - gate has insulator spacer layers sandwiching the neck portion of the t - gate . the spacer layers are thinner than the t - bar portion overhang . the insulating layer provides mechanical support and protects the vulnerable neck portion of the t - gate from chemical attack during subsequent device processing , making the t - gate structure highly scalable and improving yield . the use of thin conformal low dielectric constant insulating layers ensures a low parasitic gate capacitance , and reduces the risk of shorting gate and source metallurgy when source - to - gate spacings are reduced to smaller dimensions .