Novel CMOS-based multi-band terahertz detector for passive imaging

The existing terahertz detectors based on complementary metal oxide semiconductor cannot meet the design requirements of passive terahertz focal plane imaging chips owing to the problems of excessive noise or high-power consumption. To overcome this limitation, this study innovatively proposes using the gate of an N-type metal oxide semiconductor (NMOS) as a matching impedance of a multi-band terahertz on-chip antenna. In this way, the conversion of incident radiation into heat is achieved, and it is concentrated above the NMOS channel. The temperature characteristics of the equivalent impedance of the NMOS in the cutoff region are used to measure the incident radiated power without the DC bias current. The principle and simulation results of the proposed detector are given by system modeling, multi-band terahertz on-chip antenna design, and detector design. The experimental results show that the noise equivalent power of the proposed detector is very close to 1 pW (root Hz)(-1) under liquid nitrogen cooling, which can meet the design requirements of passive terahertz focal plane imaging chips.