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 (Δu) enhancement in an on-chip measurement as compared with our previous works using the same asymmetry ratio (ηa= 30). The inner contact diameter (din) was scaled down from 8 to 0.13 μm for the parasitic resistance limit case. By changing the ground source from inside to outside the nano-ring FET, we could generate different Δu polarities, which in turn reduced the junction leakage with improved |Δu|. From a fabricated nano-ring FET with the outer ring grounded source, we observed 5× of additional |Δu| enhancement followed by 107× with din 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/Hz0.5 were experimentally demonstrated under 0.12-THz radiation. IEEE