A fully-integrated 860-GHz CMOS terahertz sensor

This paper proposes a fully-integrated 860-GHz terahertz wave sensor. The sensor integrates a terahertz detector and readout circuit in 180-nm standard CMOS process. The readout circuit consists of a low-noise instrumentation amplifier and a high-resolution ΔΣ-ADC. Transmissive imaging without source modulation (no lock-in technique required) is realized using the sensor. The detector consists of a novel on-chip grounded patch antenna, a source-feeding NMOS field effect transistor and matching networks. A quarter-wavelength microstrip transmission line is designed to connect the gate of the NMOS transistor to eliminate the influence of bonding wire and pad. The measured maximum voltage responsivity (R_v) and minimum noise equivalent power (NEP) of the detector at 860 GHz are 3.3 kV/W and 106 pW/Hz^1/2, respectively. The measured readout circuit noise is 2. 03 μVrms.