MCM technology for RF tunable band pass filters implemented by integration of GaAs FETs and selectively oxidized porous silicon (SOPS)

RF tunable band pass filter has been implemented using the MCM-Si technology on selectively oxidized porous silicon (SOPS) substrate. The key approach of this paper is to integrate the GaAs FETs with silicon substrate to minimize the unwanted area by passive components on GaAs. All components except the active devices are fabricated on the SOPS substrate using the conventional thin film process and integrated through the wire bonding technique. This RF tunable filter has shown the center frequency from 5.64 GHz to 5.74 GHz with 0 dB insertion loss. The implemented tunable band pass filter has the Q-factor control scheme through gate bias resistor according with the frequency change. The whole area of GaAs die where all active devices have been fabricated is as small as 0.8×0.9 mm², which can be reduced to 0.6×0.7 mm²