HIGH-EFFICIENCY AND HIGHLY RELIABLE 20 W GAAS POWER FIELD-EFFECT TRANSISTOR IN C-BAND

This paper describes a high-performance and highly reliable GaAs field-effect transistor (FET) with a new gate structure employing the stepped gate recess combined with a multirefractory metal gate. This gate structure allows the simultaneous increase of maximum channel current and gate-drain breakdown voltage (V(gdo)) of the FET and thus improves significantly its output power (P(o)) and power-added efficiency (eta(add)). The resultant high V(gdo) with highly stable gate Schottky characteristics and a novel surface stabilization prior to plasma-SiN passivation effectively suppress both catastrophic and gradual failures. The four-chip internally matched device (4 x 12.6 mm) has delivered P(o) of 20 W at 1 dB gain compression with 39% eta(add) over 3.5 to 4.2 GHz. Sufficient reliability of the 20 W device available for satellite use has been assured by comprehensive reliability tests.