Investigation of self-aligned p++-GaAs/n-InGaP heterojunction field-effect transistors

Abstract p ++ -GaAs/n-InGaP heterojunction field-effect transistors (HJFETs) with a highly carbon-doped gate and a wide-gap channel were reported. A self-aligned T-shaped gate HJFET exhibits a gate of 0.6 μm in length by depositing gate metal of 1.0 μm . DC characteristics including a turn-on voltage of 2.0 V at 1 mA / mm , a gate-drain breakdown voltage up to 30 V , a drain-source breakdown voltage exceeding 25 V , a maximum available transconductance of 160 mS / mm and AC performances such as a unit-current gain frequency of 16.8 GHz , and a unit-power gain frequency of 25 GHz were obtained for a non-self-aligned HJFET. With a self-aligned processing structure, the transconductance and f max were improved to 230 mS / mm and 35 GHz , respectively.