A compound semiconductor field effect transistor (FET) may include a channel layer. The semiconductor FET may also include an oxide layer, partially surrounded by a passivation layer, on the channel layer. The semiconductor FET may also include a first dielectric layer on the oxide layer. The semiconductor FET may also include a second dielectric layer on the first dielectric layer. The semiconductor FET may further include a gate, comprising a base gate through the oxide layer and the first dielectric layer, and a head gate in the second dielectric layer and electrically coupled to the base gate.