Breakdown analysis of an asymmetrical double recessed power MESFET's

FET's with double stepped gate recess are commonly admitted to be presently a very convenient structure capable to overcome the fundamental power limitation related to the breakdown voltage. The present paper deals with an analysis of a double recessed MESFET with a very good and instructive breakdown performance. For the first time we explain on the basis of gate current observations why the double recess structure allows a large breakdown improvement not only at pinch off voltage but also at open channel. Moreover it is shown that the breakdown optimization is fully compatible with the microwave gain performance.>