Transferred Substrate

The aim of the project is to provide a terahertz technology for monolithic microwave integrated circuits (MMIC). This access to the terahertz gap (0.1 – 3 THz) of the electromagnetic spectrum opens up the unutilized range between electronics and optics.

A transferred substrate process has been developed for InP heterojunction bipolar transistor (HBT). By the removal of the epitaxial substrate it provides an aligned lithographic access to front and back side of the device. This innovative device concept enables to eliminate dominant parasitics of the transistor. Parallel to the device setup high frequency and thermal performance of the periphery is optimized.

Via 0.8 μm stepper lithography transferred substrate HBT with cut-off frequency of f_t = 410 GHz, maximum oscillation frequency f_max = 480 GHz @ BV_ceo = 5.5 V were realized and traveling wave amplifiers were prototyped.