A measurement setup for THz detectors characterization validated on FET-based CMOS test structures

A test setup and measurement methodology is presented for characterization of direct THz detectors to be used in imaging application. An active imaging setup is employed whereby the detector is illuminated by a dedicated continuous wave THz source and detector response is measured using a lock-in amplifier. The THz detector is accompanied by an on-chip antenna for the reception of THz waves and its antenna directivity is measured in both the E and H planes in order to calculate the effective pixel area of the detector. The setup employs a reference detector to measure the received input power instead of using transmitting antenna specifications. Several issues, such as the background noise arising in the setup and standing waves interference have also been taken into consideration. Based on the measured input power of the detector, performance parameters of FET based THz detector are calculated and presented.