Research on the circuit structure of THz detector in CMOS

The circuit structure is the key factor to determine the performance of CMOS THz detector. This paper presents four different structures of the terahertz detection circuit and their performance are analyzed. The common source(CS), common gate(CG), cascode and source differential circuits are designed in 0.18µm CMOS process. Under the conditions of the same input power level and transistor parameters, the key performances of four detectors are obtained and compared by the simulation with responsivity (Rv) and noise equivalent power (NEP), It is concluded that the differential input circuit has the best performance under the same conditions. At 300 GHz, the detector achieves a responsivity of 340 V/W and a noise equivalent power (NEP) of 0.967 pW/Hz0.5.