a field effect transistor is provided . the field effect transistor includes a semiconductor region formed on a substrate , wherein the semiconductor region comprises an undoped channel region , a source region including a first dopant type , and a drain region including a second dopant type , and wherein the channel region is formed of a group iii - v compound semiconductor material . the field effect transistor further includes a high - k gate formed on the channel region , wherein the high - k gate is configured to generate electron tunneling between the source region and the drain region when a gate voltage is applied , and wherein a first contact surface between the source region and the channel region and a second contact surface between the drain region and the channel region are inclined .