Terahertz image sensors using CMOS Schottky barrier diodes

Schottky-barrier diodes fabricated in CMOS without process modification are shown to be suitable for THz imaging. Two THz imagers using a 130-nm digital CMOS technology are demonstrated. A fully-integrated 280-GHz 4×4 imager array exhibits a measured NEP of 29 pW/Hz^1/2 and a responsivity of 5.1kV/W (323 V/W without the amplifier). For the first time, electronic-scanning multi-pixel imaging is demonstrated in a setup that does not require bulky and costly optical lenses and mirrors. A second detector operating at 860 GHz is also demonstrated. The detector without an amplifier achieves responsivity of 355 V/W and NEP of 32 pW/Hz^1/2. It is shown that the comparable responsivity and NEP as that of 280-GHz detector is due to the improvement of patch antenna efficiency at 860 GHz. The NEP at 860 GHz is 2X better than the best reported performance of MOSFET-based imagers without silicon lens attached to the chip.