InP HBTs for THz frequency integrated circuits

A 0.25μm InP DHBT process has been developed for THz frequency integrated circuits. A 0.25×4μm
²
HBT exhibits an extrapolated f
_t
/f
_max
of 430GHz/1.03THz at I
_C
=11mA, V
_CE
=1.8V. The transistors achieve this performance while maintaining a common-emitter breakdown voltage (BV
_CEO
)>;4V. Thin-film interconnects and backside wafer processes have been developed to support selected IC demonstrations. The technology has been used to build fundamental oscillators, amplifiers and dynamic frequency dividers all operating at >;300GHz. Additionally, increasingly complex circuits such as a full PLL have been demonstrated.