Metamorphic HEMT technologies for millimeter-wave low-noise applications

Two metamorphic composite-channel InAlAs/InGaAs based high electron mobility transistor (MHEMT) technologies have been developed for active and passive imaging applications at millimeter-wave frequencies. The first technology features a 0.07 µm gate-length in combination with an In content of 80 % in the channel. An extrinsic transit frequency (ft) of 290 GHz, an extrinsic transconductance (gm) of 1500 mS/mm and a gate-drain breakdown voltage of 2.8 V were measured. For the second MHEMT technology the In content of the channel was reduced to 65 % and the gate length was increased to 0.1 µm, resulting in an off-state breakdown voltage of 4.3 V, an extrinsic ft of 200 GHz and an extrinsic gm of 1200 mS/mm. Using these advanced MHEMT technologies, two coplanar W-band low-noise amplifier (LNA) MMICs were realized. A small-signal gain of 13 dB with an average noise figure of 2.3 dB between 80 and 100 GHz was achieved with the 70 nm gate-length process, and a linear gain of 10 dB with approximately 3 dB associated noise figure was measured within the same frequency range by applying the 100 nm technology.