35nm InP HEMT for Millimeter and Sub-Millimeter Wave Applications

A new InP HEMT process has been developed with 35nm gate length and improved Ohmic contact. A gate-source capacitance of 0.4pF/mm is achieved with the reduced gate length, a 30% improvement over our baseline 70nm device. The contact resistance is successfully reduced to 0.07 with the newly designed contact layer combined with an alloyed Au/Ge/Ni/Au Ohmic metal. Good device characteristics has been demonstrated with a transconductance as high as 2 S/mm and a cutoff frequency f_r of 420GHz. A single-stage common-source amplifier was fabricated with this new process. A peak gain of 5dB is measured at 265GHz. A MAG/MSG of 3dB at 300GHz was achieved, making the device suitable for applications at frequencies well into the millimeter-wave and even sub-millimeter-wave band.