A high-barrier gate and tri-step doped channel transistor

A new GaInP/GaAs high-barrier gate and tri-step doped channel heterostructure field-effect transistor (HFET) has been successfully fabricated and demonstrated. A very thin and heavily doped /spl delta/(p/sup +/)-GaInP layer is introduced to increase the high gate turn-on and breakdown voltage and reduce the gate leakage current. A low-medium-high tri-step doped channel structure is used to improve the output current drivability and average transconductance. In addition, a metal-semiconductor field-effect transistor (MESFET) with the same tri-step doped channel structure has also been fabricated for comparison. The studied devices show the good performances of high breakdown voltage, high output drain saturation current and flat and wide transconductance operation regimes. The measured cut-off frequency (f/sub T/) is higher than 15 GHz. From experimental results, the studied devices show good potential in high-power and large input signal circuit applications.