Integrated Circuits Based on 300 GHz fT Metamorphic HEMT Technology for Millimeter-Wave and Mixed-Signal Applications

Advanced circuits based on metamorphic HEMT (MHEMT) technologies on 4” GaAs substrates for both millimeter-wave, and mixedsignal applications are presented. Extrinsic cut-off frequencies of ft = 293 GHz and fmax = 337 GHz were achieved for a 70 nm gate length metamorphic HEMT technology. The MMIC process obtains high yield on transistor and circuit level. Single-stage low-noise amplifiers demonstrate a small signal gain of 13 dB and a noise figure of 2.8 dB at 94 GHz. An amplifier MMIC developed for D-Band operation features a gain of 15 dB at 160 GHz.The achieved results are comparable to stateof-the-art InP-based HEMT technologies. In order to realize 80 Gbit/s digital circuits, a process with 100 nm gate length enhancement type HEMTs with a transit frequency of 200 GHz is used. Three metalization layers are available for interconnects. The parasitic capacitance of the interconnects is kept low by using BCB and plated air bridge technology. Based on this process, static and dynamic frequency dividers achieve a maximum toggle frequency of 70 GHz and 108 GHz, respectively.