Toward low-NEP room-temperature THz MOSFET direct detectors in CMOS technology

This paper reports on the impact of antenna impedance frequency characteristics on a broadband low-NEP operation of THz MOSFET direct detectors. New Si-lens integrated high-impedance on-chip ring antennas were developed based on a systematic co-design procedure with MOSFET device. They allowed achieving the world record values both in terms of responsivity and noise equivalent power for detector arrays implemented in a bulk 65 nm CMOS technology. Only few representative design examples out of the complete test array are presented. A peak optical voltage responsivity (Rv) of 2200 and a minimum noise equivalent power (NEP) of 14 pW/√Hz at 200 Hz chopping frequency were measured at 724 GHz for one of the detectors, whereas some other demonstrated broadband operation with an optical NEP below 50 pW/√Hz for at least 650-970 GHz.