Design and demonstration of antenna-coupled Schottky diodes in a foundry complementary metal-oxide semiconductor technology for electronic detection of far-infrared radiation

Abstract

Electronic detection of far-infrared (FIR) radiation up to 9.74 THz is reported in a foundry complementary metal-oxide semiconductor (CMOS) technology. The detectors were fabricated with Schottky-barrier diodes (SBDs) formed in 130-nm CMOS without any process modifications. Direct-antenna matched detectors achieve a measured peak optical responsivity (RV) of 383 and 25 V/W at 4.92 and 9.74 THz, respectively, near the 5 and 10 THz fundamental frequency of the antennas. A significantly improved RV at 9.74 THz (25× compared to the MOSFET detectors and ∼2× compared to the SBD) ensures negligible impact on the system noise-equivalent power (NEP) due to the input-referred noise of the amplifier following the detector. This work also demonstrated that by incorporating the effects of plasma resonance, transit time, and FIR absorption behavior of SiO2, as well as the 3D electromagnetic simulations into the SBD model, good agreement between the measurements and simulations can be attained. The detector designed for a 10-THz operation achieves an optical NEP of 1.1 nW/√Hz at 9.74 THz in the shot-noise limit, which is comparable to that of commercially available pyro-detectors that are 50 000× larger.