Trench-type deep N-well dual guard ring for the suppression of substrate noise coupling

This article presents a study on the isolation performance of the trench-type deep n-well (DNW) dual guard ring (GR) and its effect on the suppression of the substrate digital noise coupling on a low noise amplifier (LNA) based on measurement and TCAD simulation. The trench-type DNW dual GR, in which the DNW is formed beneath the ring-shaped n-well region only, can be adopted for protecting the noise-sensitive analog/RF circuits or circuit blocks against the substrate noise. An in-depth analysis on the performance of the trench-type DNW was carried out based on both measurement and a heavy use of TCAD. The results show that the trench-type DNW dual GR exhibits comparable isolation to that of the pocket-type DNW dual GR at high frequency regime. The effect of various GR dimension parameters and GR bias conditions on the GR isolation performance was also investigated and analyzed. Furthermore, the trench-type DNW dual GR was applied to a 5.8-GHz LNA and its effect on the suppression of the substrate digital noise coupling was studied for various digital noise conditions and GR bias schemes.