Performance Enhancement of Silicon-Based Sub-Terahertz Detector by Highly Localized Plasmonic Wave in Nano-Ring FET

Abstract

A compact monolithic trantenna (transistor-antenna) device is presented for a high-performance sub-THz wave detector using 28-nm CMOS foundry process. Based on a highly localized plasmonic wave in a silicon nano-ring field-effect transistor (FET), we obtained a total 535-fold photoresponse (Delta u) enhancement in an on-chip measurement as compared with our previous works using the same asymmetry ratio (eta(a) = 30). The inner contact diameter (d(in)) was scaleddown from 8 to 0.13 mu m for the parasitic resistance limit case. By changing the ground source from inside to outside the nano-ring FET, we could generate different Delta u polarities, which in turn reduced the junction leakage with improved vertical bar Delta u vertical bar. From a fabricated nano-ring FET with the outer ring grounded source, we observed 5x of additional vertical bar Delta u vertical bar enhancement followed by 107x with d(in) scaling. In addition, based on the highly localized plasmonic wave nano-ring FET without any external gain, a record-high free-space responsivity of 12.4 kV/W and a reduced noise equivalent power of 1 pW/Hz(0.5) were experimentally demonstrated under 0.12-THz radiation.