A Terahertz Direct Detector in 22nm FD-SOI CMOS

This paper reports on the design and characterization of a CMOS based direct terahertz detector in an advanced 22nm FD-SOI technology. The nFET detector is implemented with an on-chip ring antenna fully compliant with the technology density rules. At 0.855 THz, a maximum optical responsivity and a minimum noise equivalent power (NEP) of 1.51 kV/W and 22.65 pW/HZ
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respectively were measured in a voltage mode readout at a chopping frequency of 3 kHz. In the current mode readout, a maximum responsivity of 180 mA/W and minimum NEP of 12 pW/HZ
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were measured at a chopping frequency of 120 kHz. Additionally, the effect of transistor back-gate biasing on the detector responsivity is also characterized. The detector sensitivity is comparable to the best reported room-temperature THz direct detectors in any silicon integrated technology, along with the highest reported RF operational bandwidth with NEP below 40 pW/HZ
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in the measured frequency band of 0.7-1 THz.