Crosstalk in CMOS Terahertz Detector Array With On-Chip SPR Antenna

Although surface plasmon resonance (SPR) antennas have been integrated into CMOS THz detectors as an alternative to the traditional radio-wave antenna, spatial crosstalk of SPR antenna in detector arrays remains an issue and there is little study in this field. In this paper, a CMOS THz detector array at 0.65 THz with on-chip SPR antennas is designed in standard CMOS technology and the pixel crosstalk related to the SPR antenna parameters are investigated. Simulation results show that the adjacent SPR antenna spacing significantly affect the antenna crosstalk due to the surface wave propagation. To suppress the pixel crosstalk, the adjacent SPR antenna spacing is designed as 1.65 times larger than half of the antenna size. Under the condition, the S12 parameter between the adjacent antennas is reduced to -15 dB. High antenna isolation can be further available by the increase of the isolation layer thickness of the pixel up to 1 μm. Based on the simulation results, a 1×16 THz detector array at 0.65THz was fabricated. The experimental results show that the pixels in the array achieve uniform NEP, with an average value of about 32.6 pW/Hz0.5 and a standard deviation coefficient of about 9.6%. The results can be further optimized to meet various crosstalk requirements for CMOS THz detectors.