A micromachined SiGe HBT Ultra-Wideband Low-Noise Amplifier by BiCMOS compatible ICP deep-trench technology

In this article, we demonstrate that the power gain (S ₂₁) and noise figure (NF) performances of a SiGe HBT Ultra-Wideband Low-Noise Amplifier (UWB LNA) can be remarkably improved by removing the silicon underneath the UWB LNA with BiCMOS-process compatible backside inductively-coupled-plasma (ICP) deep trench technology. The results show that increases of 1.9 dB (from 11.2 dB to 13.1 dB) and 4.2 dB (from 7.7 dB to 11.9 dB) in S ₂₁, and decreases of 0.59 dB (from 5.08 dB to 4.49 dB) and 0.74 dB (from 6.2 dB to 5.46 dB) in NF were achieved at 10 GHz and 13 GHz, respectively, for the SiGe HBT UWB LNA after the backside ICP dry etching. The excellent performances of the SiGe HBT UWB LNA with suspended inductors suggest that it is very suitable for UWB system applications. Besides, the BiCMOS-process compatible backside ICP etching technique is very promising for BiCMOS integrated circuit (IC) applications.