A Broadband Antenna-Coupled Terahertz Direct Detector in a 0.13-μm SiGe HBT Technology

This paper presents an integrated silicon-lens coupled THz direct detector. It comprises a pair of differentially driven antenna-coupled HBT transistors in common-base configuration implemented in an advanced 0.13-mu m SiGe HBT technology with f(T)/f(max) of 350/550 GHz. Based on the antenna detector co-design approach, a broadband operation with an optical noise equivalent power (NEP) lower than 40 pW/root Hz in the measured 220 GHz to 1 THz band is achieved. The detector operates in a voltage mode readout with an external resistance of 1.83 k Omega. Two device regions have been investigated. In the forward-active mode the detector achieves its minimum NEP of 1.9 pW/root Hz at 292 GHz and values less than 4.3 pW/root Hz from 275 to 525 GHz at 100 kHz chopping frequency. The maximum voltage responsivities (R-v) are 9 kV/W and around 7.5 kV/W respectively. In the saturation region the minimum measured NEP from 220 GHz to 1 THz is 5.1 pW/root Hz.