0.2-(mu)m gate-length InGaP-InGaAs DCFETs for C-band MMIC amplifier applications

A C-band In/sub 0.49/Ga/sub 0.51/P-In/sub 0.15/Ga/sub 0.85/As doped-channel FET (DCFET) monolithic power amplifier was designed and fabricated using low-k benzocyclobutene (BCB) interlayer technology. With a photosensitive low-k BCB interlayer ((epsilon)=2.7), not only can the circuitʹs passivation layer, but also the capacitor insulator, via holes, and bridge process be realized simultaneously, where the process complexity and cost can be reduced. In addition, a 0.2-(mu)m Tshaped gate InGaP-InGaAs doped-channel FET with a high current density and a high linearity is introduced to the amplifier using the e-beam lithography. This C-band power amplifier can achieve a linear power gain of 9.3 dB and an output power of 15.3 dBm, which proves that this novel MMIC process using low-k BCB interlayer technology is attractive for microwave and millimeter wave circuit applications.