Broadband Terahertz Power Detectors Based on 90-nm Silicon CMOS Transistors With Flat Responsivity Up to 2.2 THz

Abstract

We present broadband high sensitivity terahertz (THz) detectors based on 90 nm CMOS technology with the state-of-the-art performance. The devices are based on bow-tie and log-spiral antenna-coupled field-effect transistors (FETs) for the detection of free-space THz radiation (TeraFETs). We report on optimized performance, which was achieved by employing an in-house developed physics-based model during detector design and thorough device characterization under THz illumination. The implemented detector with bow-tie antenna design exhibits a nearly flat frequency response characteristic up to 2.2 THz with an optical responsivity of 45 mA/W (or 220 V/W). We have determined a minimum optical noise-equivalent power as low as 48 pW/ $\sqrt {\textsf {Hz}}$ at 0.6 THz and 70 pW/ $\sqrt {\textsf {Hz}}$ at 1.5 THz. The results obtained at 1.5 THz are better than the best narrowband TeraFETs reported in the literature at this frequency and only up to a factor of four inferior to the best narrowband devices at 0.6 THz.